DEVELOPMENT OF BLOOD-PRESSURE AND CARDIAC REFLEXES IN THE FROG PSEUDIS-PARADOXSUS

Systemic arterial blood pressure and heart rate (f(H)) were measured in unanesthetized, unrestrained larvae and adults of the paradoxical frog, Pseudis paradoxus from São Paulo State in Brazil. Four developmental groups were used, representing the complete transition from aquatic larvae to primarily air-breathing adults. f(H) (49-66 beats/min) was not significantly affected by development, whereas mean arterial blood pressure was strongly affected, being lowest in the stage 37-39 larvae (10 mmHg), intermediate in the stage 44-45 larvae (18 mmHg), and highest in the juveniles and adults (31 and 30 mmHg, respectively). Blood pressure was not significantly correlated with body mass, which was greatest in the youngest larvae and smallest in the juveniles. In the youngest larvae studied (stages 37-39), lung ventilation was infrequent, causing a slight decrease in arterial blood pressure but no change in heart rate. Lung ventilation was more frequent in stages 44-45 larvae and nearly continuous in juveniles and adults floating at the surface. Bradycardia during both forced and voluntary diving was observed in almost every advanced larva, juvenile, and adult but in only one of four young larvae. Developmentally related changes in blood pressure were not complete until metamorphosis, whereas diving bradycardia was present at an earlier stage.

LESIONS OF THE LATERAL HYPOTHALAMUS IMPAIR THE PRESSOR-RESPONSE TO CLONIDINE INJECTED INTO THE MEDIAL SEPTAL AREA OF CONSCIOUS RATS

The central injection of clonidine (an alpha-2-adrenoceptor agonist) in conscious normotensive rats produces hypertensive responses and bradycardia. The present study was performed to investigate the effect of electrolytic lesions of the lateral hypothalamus (LH) on the pressor and bradycardic responses induced by clonidine injected into the medial septal area (MSA) in conscious and unrestrained rats. Male Holtzman rats weighing 250-300 g were used. Mean arterial pressure and heart rate were recorded in sham- or bilateral LH-lesioned rats with a cerebral stainless steel cannula implanted into the MSA. The injection of clonidine (40 nmol/mu-l) into the MSA of sham rats (N = 8) produced a pressor response (36 +/- 7 mmHg, P<0.05) and bradycardia (-70 +/- 13 bpm, P<0.05) compared to saline. Fourteen days after LH-lesion (N = 9) the pressor response was reduced (9 +/- 10 mmHg, P<0.05) but no change was observed in the bradycardia (-107 +/- 24 bpm). These results show that LH is an important area involved in the pressor response to clonidine injected into the MSA of rats.

Development of a pressure nociceptive threshold testing device for evaluation of analgesics in cats

A pressure analgesiometric device was developed for unrestrained cats. Eleven cats were studied. Stimulation was via three rounded pins within a bracelet on the forearm. The pins were advanced by manual bladder inflation. Bladder pressure was measured using a strain gauge pressure transducer. The threshold was recorded at the behavioural end point. Thresholds were measured at 5 and 15 min intervals for 2-4 h, after removal/replacement of the cuff, for 120 min after SC butorphanol (0.4 mg/kg), and with mild skin inflammation at the testing site. Data were analysed using ANOVA. Pressure thresholds in untreated cats were around 150 mmHg. The minimum interval for testing was established as 15 min. Data were reproducible over 4 h and beyond 24 h. Thresholds in 5 cats increased (P < 0.05) above baseline for 45 min after butorphanol with a maximum increase of 270 +/- 182 mmHg at 10 min. Thresholds decreased with inflammation. The method appears suitable for feline analgesia investigations. (c) 2006 Elsevier Ltd. All rights reserved.

SEX-RELATED DIFFERENCES IN CARDIOVASCULAR-RESPONSES TO COMMON CAROTID OCCLUSION IN CONSCIOUS RATS

Mean arterial pressure and heart rate were determined in conscious, unrestrained groups of 10 male, female and androgenized female Wistar rats 20 s (early pressor response) and 1 min (late sustained response) after bilateral carotid artery occlusion. The early pressor response, which is of carotid reflex origin, was 40% greater in female than in male rats (45 +/- 2 vs 63 +/- 3 mmHg, respectively). The late sustained response, which is of central origin (probably ischemic), did not differ between male and female rats (32 +/- 2 vs 37 +/- 4 mmHg, respectively). The magnitude of the early pressor response of androgenized female tats (50 +/- 2 mmHg) was similar to that of male rats (45 +/- 2 mmHg) but the late sustained response was 19% smaller (26 +/- 2 mmHg). Common carotid occlusion caused increases in heart rate which were greater in female (51 +/- 9 and 34 +/- 9 beats/min in the early pressor response and late sustained response, respectively) than in male rats (31 +/- 5 and 8 +/- 4 beats/min, respectively). In androgenized female rats, heart rate decreased during common carotid occlusion (34 +/- 7 and 35 +/- 8 beats/min after 20 s and 1 min, respectively). These data provide evidence that there are substantial sex-related differences in the cardiovascular responses to common carotid occlusion in conscious rats and indicate that administration of androgens to newborn female rats affects the baroreceptor reflex control of their arterial pressure.

Práticas do ecodesign no polo de jóias folheadas de Limeira: um estudo de caso

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The hypotensive effect of the ruthenium complex [Ru(terpy)(bdq)NO](3+) is higher in male than in female spontaneously hypertensive rats (SHR)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O tabaco é um dos principais fatores etiológicos do câncer bucal: conceitos atuais

Neoplasm, tumor or cancer generic synonymies are used to designate a group of diseases that affect any part of the body.Their main common feature is the abnormal cell proliferation, usually rapid, uncontrolled and unrestrained. According to World HealthOrganization (WHO) cancer is the leading cause of death worldwide. In 2005, a total of 58 million deaths, 7.6 million (or 13%) of all of them were cancer. Among the factors that favor its development, the tobacco is considered one of the main villains. Therefore, this article, we will discuss the basics and updates about oral cancer and tobacco consumption.