Torpor in three species of Brazilian hummingbirds under semi-natural conditions

We measured body temperatures in three species of Brazilian hummingbirds, the Versicolored Emerald (Amazilia versicolor; body mass 4.1 g), the Black Jacobin (Me lantrochilus fuscus; body mass 7.7 g) and the Swallow-tailed Hummingbird (Eupetomena macroura; body mass 8.6 g), during overnight exposure to natural conditions of photoperiod and ambient temperatures. All three species entered torpor. In both A. versicolor and E. macroura, individuals entered torpor even if they had access to feeders up to the time of sunset. In contrast, M. fuscus was less prone to enter torpor and did so mainly if it had been fasting for more than two hours before sunset. Furthermore, M. fuscus often spent the whole night in torpor, whereas the two other species entered torpor for a variable, often short, period of the night. We observed more than one torpor bout during a single night in all three species. We suggest that multiple nocturnal torpors result from interruption of the normal torpor pattern by some (unknown) external stimuli. Any interrupted torpor was always followed by a new entry into torpor, supporting the view that there is a body mass threshold below which the hummingbirds must enter torpor Our data also indicate that these hummingbird species might use torpor even if they are not energetically stressed.

Ionotropic but not metabotropic glutamatergic receptors in the locus coeruleus modulate the hypercapnic ventilatory response in unanaesthetized rats

Aim: Central chemoreceptors are important to detect changes of CO2/H+, and the Locus coeruleus (LC) is one of the many putative central chemoreceptor sites. Here, we studied the contribution of LC glutamatergic receptors on ventilatory, cardiovascular and thermal responses to hypercapnia. Methods: To this end, we determined pulmonary ventilation (VE), body temperatures (Tb), mean arterial pressure (MAP) and heart rate (HR) of male Wistar rats before and after unilateral microinjection of kynurenic acid (KY, an ionotropic glutamate receptor antagonist, 10 nmol/0.1 μL) or α-methyl-4-carboxyphenylglycine (MCPG, a metabotropic glutamate receptor antagonist, 10 nmol/0.1 μL) into the LC, followed by 60 min of air breathing or hypercapnia exposure (7% CO2). Results: Ventilatory response to hypercapnia was higher in animals treated with KY intra-LC (1918.7 ± 275.4) compared with the control group (1057.8 ± 213.9, P < 0.01). However, the MCPG treatment within the LC had no effect on the hypercapnia-induced hyperpnea. The cardiovascular and thermal controls were not affected by hypercapnia or by the injection of KY and MCPG in the LC. Conclusion: These data suggest that glutamate acting on ionotropic, but not metabotropic, receptors in the LC exerts an inhibitory modulation of hypercapnia-induced hyperpnea. © 2013 Scandinavian Physiological Society.

Anestesia espinhal no lagarto Iguana iguana (Linnaeus, 1758)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelagem do equilíbrio térmico de frangos de corte: um estudo da geração e transferência de calor

Pós-graduação em Zootecnia - FCAV

Termofisiolofia da vespa Polybia (Trichothorax) ignobilis (Haliday, 1836) (Hymenoptera, Vespidae, Epiponini) durante a atividade de forrageamento

Many social wasps are known to use thermogenesis to warm up their flight muscles and are therefore able to forage under a broad range of ambient temperatures. However it is uncertain whether there exists a possible relation between ambient temperature and thermogenic capacity for tropical species, as we lack studies focusing on these species. Therefore, we examined the use of this mechanism in the neotropical Epiponini wasp Polybia ignobilis. More specifically, we used a thermographic camera to obtain data of the surface temperatures of three body regions (head, thorax and abdomen) of wasps during foraging activities (pre-flight, flight and post-flight) in cold [initial pe- riod of foraging activity: TAM : 15 − 20◦C] and warm [final period of foraging activity: TPM : 30 − 35◦C] conditions. Thorax temperature (Tth) was always higher than head (Th) and abdomen temperature (Tabd). In general, the lowest body temperatures were observed during the pre-flight period, while the highest values occurred upon the return of the wasps from the foraging flight. Except for the pre-flight period, Tth was always higher than Tabd, indicating that heat generated at the thorax was preferentially directed to the cephalic region. Therefore we confirmed the use of thermogenesis by a neotropical social wasp, although its magnitude was found modest compared to temperate species, which suggests a link between thermal environment and thermogenic capacity. We also showed that P. ignobilis modulates heat production as a function of ambient temperature (TA), maintaining a greater temperature difference (Tbody − TA) at cooler temperatures. Finally, we identified the cephalic region of wasps as an important route for the dissipation of the heat generated during flight

Influência da temperatura e do termoperíodo sobre a taxa metabólica de repouso em cascavéis, Crotalus durissus (Serpentes: Viperidae)

Snakes are ectothermic animals and, therefore, their physiological functions are strongly affected by temperature. For instance, the resting metabolic rate (RMR) of this animals increase with the rise in body temperature. However, metabolic determinations in ectothermic organisms, including snakes, are generally made by submitting the animals to constant temperature regimes. This experimental procedure, although widely used, accepted and certainly suitable in several cases, submit the animals to a very different situation from that experienced by them in nature. In fact, ectothermics are known by presenting extensive variations in their body temperatures trough the day and/or seasons. If this disagreement between the thermal biology of the animals and the experimental conditions, for instance over the circadian cycle, affects the determinations of metabolic rates of ectotherm animals, remains quite uncertain. Thus, this study aimed to test the effects of different thermal regimes (fluctuating vs constant) in different temperature ranges over the TMR of rattlesnakes (Crotalus durissus). Therefore, the TMR of rattlesnakes was measured by the oxygen consumption rates ( V O2) in the constant temperatures of 15°C, 20°C, 25°C, 30°C and 35°C. For fluctuating regimes, snakes were measured in thermoperiods of 12/12 hours, as follows: 15°C and 25°C; 20°C and 30°C; 25°C and 35°C. Our results show that the RMR of C. durissus rises as the temperature increases, regardless of the thermal regime. The obtained RMR in the constant regimes of 20°C and 25°C was not different from that measured in the correspondent fluctuating regimes (i.e., 15 - 25°C e 20 - 30°C). However, at constant 30°C, the RMR was significantly higher than that obtained in the 30°C fluctuating regime (25 - 35ºC). This indicates that the potential effects in submitting of snakes to different thermal regimes of its thermal biology become more important with...

Termofisiolofia da vespa Polybia (Trichothorax) ignobilis (Haliday, 1836) (Hymenoptera, Vespidae, Epiponini) durante a atividade de forrageamento

Many social wasps are known to use thermogenesis to warm up their flight muscles and are therefore able to forage under a broad range of ambient temperatures. However it is uncertain whether there exists a possible relation between ambient temperature and thermogenic capacity for tropical species, as we lack studies focusing on these species. Therefore, we examined the use of this mechanism in the neotropical Epiponini wasp Polybia ignobilis. More specifically, we used a thermographic camera to obtain data of the surface temperatures of three body regions (head, thorax and abdomen) of wasps during foraging activities (pre-flight, flight and post-flight) in cold [initial pe- riod of foraging activity: TAM : 15 − 20◦C] and warm [final period of foraging activity: TPM : 30 − 35◦C] conditions. Thorax temperature (Tth) was always higher than head (Th) and abdomen temperature (Tabd). In general, the lowest body temperatures were observed during the pre-flight period, while the highest values occurred upon the return of the wasps from the foraging flight. Except for the pre-flight period, Tth was always higher than Tabd, indicating that heat generated at the thorax was preferentially directed to the cephalic region. Therefore we confirmed the use of thermogenesis by a neotropical social wasp, although its magnitude was found modest compared to temperate species, which suggests a link between thermal environment and thermogenic capacity. We also showed that P. ignobilis modulates heat production as a function of ambient temperature (TA), maintaining a greater temperature difference (Tbody − TA) at cooler temperatures. Finally, we identified the cephalic region of wasps as an important route for the dissipation of the heat generated during flight

Influência da temperatura e do termoperíodo sobre a taxa metabólica de repouso em cascavéis, Crotalus durissus (Serpentes: Viperidae)

Snakes are ectothermic animals and, therefore, their physiological functions are strongly affected by temperature. For instance, the resting metabolic rate (RMR) of this animals increase with the rise in body temperature. However, metabolic determinations in ectothermic organisms, including snakes, are generally made by submitting the animals to constant temperature regimes. This experimental procedure, although widely used, accepted and certainly suitable in several cases, submit the animals to a very different situation from that experienced by them in nature. In fact, ectothermics are known by presenting extensive variations in their body temperatures trough the day and/or seasons. If this disagreement between the thermal biology of the animals and the experimental conditions, for instance over the circadian cycle, affects the determinations of metabolic rates of ectotherm animals, remains quite uncertain. Thus, this study aimed to test the effects of different thermal regimes (fluctuating vs constant) in different temperature ranges over the TMR of rattlesnakes (Crotalus durissus). Therefore, the TMR of rattlesnakes was measured by the oxygen consumption rates ( V O2) in the constant temperatures of 15°C, 20°C, 25°C, 30°C and 35°C. For fluctuating regimes, snakes were measured in thermoperiods of 12/12 hours, as follows: 15°C and 25°C; 20°C and 30°C; 25°C and 35°C. Our results show that the RMR of C. durissus rises as the temperature increases, regardless of the thermal regime. The obtained RMR in the constant regimes of 20°C and 25°C was not different from that measured in the correspondent fluctuating regimes (i.e., 15 - 25°C e 20 - 30°C). However, at constant 30°C, the RMR was significantly higher than that obtained in the 30°C fluctuating regime (25 - 35ºC). This indicates that the potential effects in submitting of snakes to different thermal regimes of its thermal biology become more important with...

Opioid mu-receptors in the rostral medullary raphe modulate hypoxia-induced hyperpnea in unanesthetized rats

Aim: It has been suggested that the medullary raphe (MR) plays a key role in the physiological responses to hypoxia. As opioid mu-receptors have been found in the MR, we studied the putative role of opioid mu-receptors in the rostral MR (rMR) region on ventilation in normal and 7% hypoxic conditions. Methods: We measured pulmonary ventilation ((V) over dotE) and the body temperatures (Tb) of male Wistar rats before and after the selective opioid l-receptor antagonist CTAP ( d-Phe-Cys-Tyr-d-Trp-Arg-Thr-Pen-Thr-NH2, cyclic, 0.1 mu g per 0.1 mu L) was microinjected into the rMR during normoxia or after 60 min of hypoxia. Results: The animals treated with intra-rMR CTAP exhibited an attenuation of the ventilatory response to hypoxia ( 430 +/- 86 mL kg) 1 min) 1) compared with the control group ( 790 +/- 82 mL kg) 1 min) 1) ( P < 0.05). No differences in the Tb were observed between groups during hypoxia. Conclusion: These data suggest that opioids acting on l-receptors in the rMR exert an excitatory modulation of hyperventilation induced by hypoxia.

Frequent Arousal from Hibernation Linked to Severity of Infection and Mortality in Bats with White-Nose Syndrome

White-nose syndrome (WNS), an emerging infectious disease that has killed over 5.5 million hibernating bats, is named for the causative agent, a white fungus (Geomyces destructans (Gd)) that invades the skin of torpid bats. During hibernation, arousals to warm (euthermic) body temperatures are normal but deplete fat stores. Temperature-sensitive dataloggers were attached to the backs of 504 free-ranging little brown bats (Myotis lucifugus) in hibernacula located throughout the northeastern USA. Dataloggers were retrieved at the end of the hibernation season and complete profiles of skin temperature data were available from 83 bats, which were categorized as: (1) unaffected, (2) WNS-affected but alive at time of datalogger removal, or (3) WNS-affected but found dead at time of datalogger removal. Histological confirmation of WNS severity (as indexed by degree of fungal infection) as well as confirmation of presence/absence of DNA from Gd by PCR was determined for 26 animals. We demonstrated that WNS-affected bats aroused to euthermic body temperatures more frequently than unaffected bats, likely contributing to subsequent mortality. Within the subset of WNS-affected bats that were found dead at the time of datalogger removal, the number of arousal bouts since datalogger attachment significantly predicted date of death. Additionally, the severity of cutaneous Gd infection correlated with the number of arousal episodes from torpor during hibernation. Thus, increased frequency of arousal from torpor likely contributes to WNS-associated mortality, but the question of how Gd infection induces increased arousals remains unanswered.

Ketoprofen in piglets: enantioselective pharmacokinetics, pharmacodynamics and PK/PD modelling

The chiral pharmacokinetics and pharmacodynamics of ketoprofen were investigated in a placebo-controlled study in piglets after intramuscular administration of 6 mg/kg racemic ketoprofen. The absorption half-lives of both enantiomers were short, and S-ketoprofen predominated over R-ketoprofen in plasma. A kaolin-induced inflammation model was used to evaluate the anti-inflammatory, antipyretic and analgesic effects of ketoprofen. Skin temperatures increased after the kaolin injection, but the effect of ketoprofen was small. No significant antipyretic effects could be detected, but body temperatures tended to be lower in the ketoprofen-treated piglets. Mechanical nociceptive threshold testing was used to evaluate the analgesic effects. The piglets in the ketoprofen-treated group had significantly higher mechanical nociceptive thresholds compared to the piglets in the placebo group for 12-24 h following the treatment. Pharmacokinetic/pharmacodynamic modelling of the results from the mechanical nociceptive threshold testing gave a median IC(50) for S-ketoprofen of 26.7 mug/mL and an IC(50) for R-ketoprofen of 1.6 mug/mL. This indicates that R-ketoprofen is a more potent analgesic than S-ketoprofen in piglets. Estimated ED(50) for racemic ketoprofen was 2.5 mg/kg.

Humoral response to 2 inactivated bluetongue virus serotype-8 vaccines in South American camelids

BACKGROUND: Bluetongue virus serotype 8 (BTV-8) has caused disease in domestic ruminants in several countries of northern Europe since 2006. In 2008 a mass-vaccination program was launched in most affected countries using whole virus inactivated vaccines. OBJECTIVE: To evaluate 2 inactivated vaccines (Bovilis BTV 8; BTVPUR AlSap8) for immunogenicity and safety against BTV-8 in South American camelids (SAC) in a field trial. ANIMALS: Forty-two SAC (25 Alpacas, 17 Llamas) aged between 1 and 16 years. METHODS: The animals were vaccinated twice at intervals of 21 days. They were observed clinically for adverse local, systemic, or both reactions throughout the trial. Blood samples collected on days 0, 14, 21, 43, and 156 after vaccination were tested for the presence of BTV-8 virus by real time-polymerase chain reaction and of specific antibodies by competitive ELISA and a serum neutralization test. RESULTS: All vaccinated animals developed antibodies to BTV-8 after the 2nd administration of the vaccine. No adverse effects were observed except for moderate local swellings at the injection site, which disappeared within 21 days. Slightly increased body temperatures were only observed in the first 2 days after vaccination. The BTV was not detected in any of the samples analyzed. CONCLUSIONS AND CLINICAL IMPORTANCE: The administration of the 2 inactivated commercial vaccines was safe and induced seroconversion against BTV-8 in all vaccinated animals. The results of this study suggest that 2 doses injected 3 weeks apart is a suitable vaccination regimen for SAC.

Complicated intra-abdominal infections in Europe: preliminary data from the first three months of the CIAO Study

The CIAO Study is a multicenter observational study currently underway in 66 European medical institutions over the course of a six-month study period (January-June 2012).This preliminary report overviews the findings of the first half of the study, which includes all data from the first three months of the six-month study period.Patients with either community-acquired or healthcare-associated complicated intra-abdominal infections (IAIs) were included in the study.912 patients with a mean age of 54.4 years (range 4-98) were enrolled in the study during the first three-month period. 47.7% of the patients were women and 52.3% were men. Among these patients, 83.3% were affected by community-acquired IAIs while the remaining 16.7% presented with healthcare-associated infections. Intraperitoneal specimens were collected from 64.2% of the enrolled patients, and from these samples, 825 microorganisms were collectively identified.The overall mortality rate was 6.4% (58/912). According to univariate statistical analysis of the data, critical clinical condition of the patient upon hospital admission (defined by severe sepsis and septic shock) as well as healthcare-associated infections, non-appendicular origin, generalized peritonitis, and serious comorbidities such as malignancy and severe cardiovascular disease were all significant risk factors for patient mortality.White Blood Cell counts (WBCs) greater than 12,000 or less than 4,000 and core body temperatures exceeding 38°C or less than 36°C by the third post-operative day were statistically significant indicators of patient mortality.

[Neuromonitoring and neuroprotection in cardiac anaesthesia. Nationwide survey conducted by the Cardiac Anaesthesia Working Group of the German Society of Anaesthesiology and Intensive Care Medicine]

OBJECTIVE: The primary objective of this nationwide survey carried out in department of cardiac anesthesia in Germany was to identify current practice with regard to neuromonitoring und neuroprotection. METHODOLOGY: The data are based on a questionnaire sent out to all departments of cardiac anesthesia in Germany between October 2007 und January 2008. The anonymized questionnaire contained 26 questions about the practice of preoperative evaluation of cerebral vessels, intra-operative use of neuromonitoring, the nature und application of cerebral protective measures, perfusion management during cardiopulmonary bypass, postoperative evaluation of neurological status, and training in the field of cerebral monitoring. RESULTS: Of the 80 mailed questionnaires 55% were returned and 90% of department evaluated cerebral vessels preoperatively with duplex ultrasound. The methods used for intra-operative neuromonitoring are electroencephalography (EEG, 60%) for type A dissections (38.1%), for elective surgery on the thoracic and thoraco-abdominal aorta (34.1% and 31.6%, respectively) and in carotid surgery (43.2%) near infrared spectroscopy (40%), evoked potentials (30%) and transcranial Doppler sonography (17.5%), with some centers using combined methods. In most departments the central nervous system is not subjected to monitoring during bypass surgery, heart valve surgery, or minimally invasive surgery. Cerebral protective measures used comprise patient cooling on cardio-pulmonary bypass (CPB 100%), extracorporeal cooling of the head (65%) and the administration of corticosteroids (58%), barbiturates (50%) and antiepileptic drugs (10%). Neuroprotective anesthesia consists of administering inhalation anesthetics (32.5%; sevoflurane 76.5%) and intravenous anesthesia (20%; propofol and barbiturates each accounting for 46.2%). Of the departments 72.5% cool patients as a standard procedure for surgery involving cardiovascular arrest and 37.5% during all surgery using CPB. In 84.6% of department CPB flow equals calculated cardiac output (CO) under normothermia, while the desired mean arterial pressure (MAP) varies between 60 and 70 mmHg (43.9%) and between 50 and 60 mmHg (41.5%), respectively. At body temperatures less than 18 degrees C CPB flow is reduced below the calculated CO (70%) while 27% of departments use normothermic flow rates. The preferred MAP under hypothermia is between 50 and 60 mmHg (59%). The results of intra-operative neuromonitoring are documented on the anesthesia record (77%). In 42.5% of the departments postoperative neurological function is estimated by the anesthesiologist. Continuing education sessions pertaining to neuromonitoring are organized on a regular basis in 32.5% of the departments and in 37.5% individual physicians are responsible for their own neuromonitoring education. CONCLUSION: The present survey data indicate that neuromonitoring and neuroprotective therapy during CPB is not standardized in cardiac anesthesiology departments in Germany. The systemic use of available methods to implement multimodal neuromonitoring would be desirable.

Pleasant sweeping grooming touch in rhesus monkey: effects on autonomic nervous system and its codification in posterior insular and secondary somatosensory cortex

Il tatto assume un'importanza fondamentale nella vita quotidiana, in quanto ci permette di discriminare le caratteristiche fisiche di un oggetto specifico, di identificarlo e di eventualmente integrare le suddette informazioni tattili con informazioni provenienti da altri canali sensoriali. Questa è la componente sensoriale-discriminativa del tatto. Tuttavia quotidianamente il tatto assume un ruolo fondamentale durante le diverse interazioni sociali, positive, come quando abbracciamo o accarezziamo una persona con cui abbiamo un rapporto affettivo e negative, per esempio quando allontaniamo una persona estranea dal nostro spazio peri-personale. Questa componente è la cosiddetta dimensione affettiva-motivazionale, la quale determina la codifica della valenza emotiva che l'interazione assume. Questa componente ci permette di creare, mantenere o distruggere i legami sociali in relazione al significato che il tocco assume durante l'interazione. Se per esempio riceviamo una carezza da un familiare, questa verrà percepita come piacevole e assumerà un significato affiliativo. Questo tipo di tocco è comunente definito come Tocco Sociale (Social Touch). Gli aspetti discriminativi del tatto sono stati ben caratterizzati, in quanto storicamente, il ruolo del tatto è stato considerato quello di discriminare le caratteristiche di ciò che viene toccato, mentre gli aspetti affettivi sono stati solo recentemente indagati considerando la loro importanza nelle interazioni sociali. Il tocco statico responsabile dell'aspetto discriminante attiva a livello della pelle le grandi fibre mieliniche (Aβ), modulando a livello del sistema nervoso centrale le cortecce sensoriali, sia primarie che secondarie. Questo permette la codifica a livello del sistema nervoso centrale delle caratteristiche fisiche oggettive degli oggetti toccati. Studi riguardanti le caratteristiche del tocco affiliativo sociale hanno messo in evidenza che suddetta stimolazione tattile 1) è un particolare tocco dinamico che avviene sul lato peloso delle pelle con una velocità di 1-10 cm/sec; 2) attiva le fibre amieliniche (fibre CT o C-LTMRs); 3) induce positivi effetti autonomici, ad esempio la diminuzione della frequenza cardiaca e l'aumento della variabilità della frequenza cardiaca; e 4) determina la modulazione di regioni cerebrali coinvolte nella codifica del significato affiliativo dello stimolo sensoriale periferico, in particolare la corteccia insulare. Il senso del tatto, con le sue due dimensioni discriminativa e affiliativa, è quotidianamente usato non solo negli esseri umani, ma anche tra i primati non umani. Infatti, tutti i primati non umani utilizzano la componente discriminativa del tatto per identificare gli oggetti e il cibo e l'aspetto emotivo durante le interazioni sociali, sia negative come durante un combattimento, che positive, come durante i comportamenti affiliativi tra cui il grooming. I meccanismi di codifica della componente discriminativa dei primati non umani sono simili a quelli umani. Tuttavia, si conosce ben poco dei meccanismi alla base della codifica del tocco piacevole affiliativo. Pur essendo ben noto che i meccanorecettori amilienici C-LTMRs sono presenti anche sul lato peloso della pelle dei primati non umani, attualmente non ci sono studi riguardanti la correlazione tra il tocco piacevole e la loro modulazione, come invece è stato ampiamente dimostrato nell'uomo. Recentemente è stato ipotizzato (Dunbar, 2010) il ruolo delle fibre C-LTMRs durante il grooming, in particolare durante il cosiddetto swepping. Il grooming è costituito da due azioni motorie, lo sweeping e il picking che vengono eseguite in modo ritmico. Durante lo sweeping la scimmia agente muove il pelo della scimmia ricevente con un movimento a mano aperta, per poter vedere il preciso punto della pelle dove eseguire il picking, ovvero dove prendere la pelle a livello della radice del pelo con le unghie dell'indice e del pollice e tirare per rimuovere parassiti o uova di parassiti e ciò che è rimasto incastrato nel pelo. Oltre il noto ruolo igenico, il grooming sembra avere anche una importante funzione sociale affiliativa. Come la carezza nella società umana, cosi il grooming tra i primati non umani è considerato un comportamento. Secondo l'ipotesi di Dunbar l'attivazione delle C-LTMRs avverrebbe durante lo sweeping e questo porta a supporre che lo sweeping, come la carezza umana, costituisca una componente affiliativa del grooming, determinando quindi a contribuire alla sua codifica come comportamento sociale. Fino ad ora non vi è però alcuna prova diretta a sostegno di questa ipotesi. In particolare, 1) la velocità cui viene eseguito lo sweeping è compatibile con la velocità di attivazione delle fibre CT nell'uomo e quindi con la velocità tipica della carezza piacevole di carattere sociale affiliativo (1-10 cm/sec)?; 2) lo sweeping induce la stessa modulazione del sistema nervoso autonomo in direzione della modulazione del sistema vagale, come il tocco piacevole nell'uomo, attraverso l'attivazione delle fibre CT?; 3) lo sweeping modula la corteccia insulare, cosi come il tocco piacevole viene codificato come affiliativo nell'uomo mediante le proiezioni delle fibre CT a livello dell'insula posteriore? Lo scopo del presente lavoro è quella di testare l'ipotesi di Dunbar sopra citata, cercando quindi di rispondere alle suddette domande. Le risposte potrebbero consentire di ipotizzare la somiglianza tra lo sweeping, caratteristico del comportamento affiliativo di grooming tra i primati non umani e la carezza. In particolare, abbiamo eseguito 4 studi pilota. Nello Studio 1 abbiamo valutato la velocità con cui viene eseguito lo sweeping tra scimmie Rhesus, mediante una analisi cinematica di video registrati tra un gruppo di scimmie Rhesus. Negli Studi 2 e 3 abbiamo valutato gli effetti sul sistema nervoso autonomo dello sweeping eseguito dallo sperimentatore su una scimmia Rhesus di sesso maschile in una tipica situazione sperimentale. La stimolazione tattile è stata eseguita a diverse velocità, in accordo con i risultati dello Studio 1 e degli studi umani che hanno dimostrato la velocità ottimale e non ottimale per l'attivazione delle C-LTMRs. In particolare, nello Studio 2 abbiamo misurato la frequenza cardiaca e la variabilità di questa, come indice della modulatione vagale, mentre nello Studio 3 abbiamo valutato gli effetti dello sweeping sul sistema nervoso autonomo in termini di variazioni di temperatura del corpo, nello specifico a livello del muso della scimmia. Infine, nello Studio 4 abbiamo studiato il ruolo della corteccia somatosensoriale secondaria e insulare nella codifica dello sweeping. A questo scopo abbiamo eseguito registrazioni di singoli neuroni mentre la medesima scimmia soggetto sperimentale dello Studio 2 e 3, riceveva lo sweeping a due velocità, una ottimale per l'attivazione delle C-LTMRs secondo gli studi umani e i risultati dei tre studi sopra citati, ed una non ottimale. I dati preliminari ottenuti, dimostrano che 1) (Studio 1) lo sweeping tra scimmie Rhesus viene eseguito con una velocità media di 9.31 cm/sec, all'interno dell'intervallo di attivazione delle fibre CT nell'uomo; 2) (Studio 2) lo sweeping eseguito dallo sperimentatore sulla schiena di una scimmia Rhesus di sesso maschile in una situazione sperimentale determina una diminuzione della frequenza cardiaca e l'aumento della variabilità della frequenza cardiaca se eseguito alla velocità di 5 e 10 cm/sec. Al contrario, lo sweeping eseguito ad una velocità minore di 1 cm/sec o maggiore di 10 cm/sec, determina l'aumento della frequenza cardiaca e la diminuzione della variabilità di questa, quindi il decremento dell'attivazione del sistema nervoso parasimpatico; 3) (Studio 3) lo sweeping eseguito dallo sperimentatore sulla schiena di una scimmia Rhesus di sesso maschile in una situazione sperimentale determina l'aumento della temperatura corporea a livello del muso della scimmia se eseguito alla velocità di 5-10 cm/sec. Al contrario, lo sweeping eseguito ad una velocità minore di 5 cm/sec o maggiore di 10 cm/sec, determina la diminuzione della temperatura del muso; 4) (Studio 4) la corteccia somatosensoriale secondaria e la corteccia insulare posteriore presentano neuroni selettivamente modulati durante lo sweeping eseguito ad una velocità di 5-13 cm/sec ma non neuroni selettivi per la codifica della velocità dello sweeping minore di 5 cm/sec. Questi risultati supportano l'ipotesi di Dunbar relativa al coinvolgimento delle fibre CT durante lo sweeping. Infatti i dati mettono in luce che lo sweeping viene eseguito con una velocità (9.31 cm/sec), simile a quella di attivazione delle fibre CT nell'uomo (1-10 cm/sec), determina gli stessi effetti fisiologici positivi in termini di frequenza cardiaca (diminuzione) e variabilità della frequenza cardiaca (incremento) e la modulazione delle medesime aree a livello del sistema nervoso centrale (in particolare la corteccia insulare). Inoltre, abbiamo dimostrato per la prima volta che suddetta stimolazione tattile determina l'aumento della temperatura del muso della scimmia. Il presente studio rappresenta la prima prova indiretta dell'ipotesi relativa alla modulazione del sistema delle fibre C-LTMRs durante lo sweeping e quindi della codifica della stimolazione tattile piacevole affiliativa a livello del sistema nervoso centrale ed autonomo, nei primati non umani. I dati preliminari qui presentati evidenziano la somiglianza tra il sistema delle fibre CT dell'uomo e del sistema C-LTMRs nei primati non umano, riguardanti il Social Touch. Nonostante ciò abbiamo riscontrato alcune discrepanze tra i risultati da noi ottenuti e quelli invece ottenuti dagli studi umani. La velocità media dello sweeping è di 9.31 cm / sec, rasente il limite superiore dell’intervallo di velocità che attiva le fibre CT nell'uomo. Inoltre, gli effetti autonomici positivi, in termini di battito cardiaco, variabilità della frequenza cardiaca e temperatura a livello del muso, sono stati evidenziati durante lo sweeping eseguito con una velocità di 5 e 10 cm/sec, quindi al limite superiore dell’intervallo ottimale che attiva le fibre CT nell’uomo. Al contrario, lo sweeping eseguito con una velocità inferiore a 5 cm/sec e superiore a 10 cm/sec determina effetti fisiologici negativo. Infine, la corteccia insula sembra essere selettivamente modulata dallo stimolazione eseguita alla velocità di 5-13 cm/sec, ma non 1-5 cm/sec. Quindi, gli studi sul sistema delle fibre CT nell’uomo hanno dimostrato che la velocità ottimale è 1-10 cm/sec, mentre dai nostri risultati la velocità ottimale sembra essere 5-13 cm / sec. Quindi, nonostante l'omologia tra il sistema delle fibre CT nell'umano deputato alla codifica del tocco piacevole affiliativo ed il sistema delle fibre C-LTMRs nei primati non umani, ulteriori studi saranno necessari per definire con maggiore precisione la velocità ottimale di attivazione delle fibre C-LTMR e per dimostrare direttamente la loro attivazione durante lo sweeping, mediante la misurazione diretta della loro modulazione. Studi in questa direzione potranno confermare l'omologia tra lo sweeping in qualità di tocco affiliativo piacevole tra i primati non umani e la carezza tra gli uomini. Infine, il presente studio potrebbe essere un importante punto di partenza per esplorare il meccanismo evolutivo dietro la trasformazione dello sweeping tra primati non umani, azione utilitaria eseguita durante il grooming, a carezza, gesto puramente affiliativo tra gli uomini.