PARAVENTRICULAR AND SUPRAOPTIC NUCLEI OF THE HYPOTHALAMUS MEDIATE CARDIOVASCULAR RESPONSES EVOKED BY THE MICROINJECTION OF NORADRENALINE INTO THE MEDIAL AMYGDALOID NUCLEUS OF THE RAT BRAIN

The medial amygdaloid nucleus (MeA) is a part of the limbic system and is involved in cardiovascular modulation. We previously reported that microinjection of noradrenaline (NA) into the MeA of unanesthetized rats caused pressor and bradycardiac responses, which were mediated by acute vasopressin release into the systemic circulation. In the present study, we tested the possible involvement of magnocellular neurons of the paraventricular (PVN) and/or supraoptic (SON) of the hypothalamus that synthesize vasopressin in the cardiovascular pathway activated by the microinjection of NA into the MeA. Pressor and bradycardiac responses to the microinjection of NA (27 nmol/100 nL) into the MeA were blocked by pretreatment of either the PVN or the SON with cobalt chloride (CoCl2, 1 mM/100 nL), thus indicating that both hypothalamic nuclei mediate the cardiovascular responses evoked by microinjection of NA Into the MeA. Our results suggest that the pressor and bradycardiac response caused by the microinjection of NA into the MeA is mediated by magnocellular neurons in both the PVN and SON. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Divergent Roles of the CRH Receptors in the Control of Gonadotropin Secretion Induced by Acute Restraint Stress at Proestrus

CRH has been implicated as a mediator of stress-induced effects on the hypothalamus-pituitary-gonad axis, acting via CRH receptors in various brain regions. We investigated whether the effects of restraint stress on the secretion of gonadotropins on the morning of proestrus are mediated by the CRH-R1 or CRH-R2 receptors in the oval subdivision of the anterolateral BST, the central amygdala, the locus coeruleus (LC), or the A1 and A2 neuron groups in the medulla. At proestrus morning, rats were injected with antalarmin (a CRH-R1 antagonist), asstressin2-B (a CRH-R2 antagonist) or vehicles. Thirty minutes after the injection, the animals were placed into restraints for 30 min, and blood was sampled for 2 h. At the end of the experiment, the brains were removed for immunofluorescence analyses. Restraint stress increased the levels of FSH and LH. Antalarmin blocked the stress-induced increases in FSH and LH secretion, but astressin2-B only blocked the increase in FSH secretion. LC showed intense stress-induced neuronal activity. FOS/tyrosine-hydroxylase coexpression in LC was reduced by antalarmin, but not astressin2-B. The CRH-R1 receptor, more than CRH-R2 receptor, appears to be essential for the stimulation of the hypothalamus-pituitary-gonad axis by acute stress; this response is likely mediated in part by noradrenergic neurons in the LC. We postulate that the stress-induced facilitation of reproductive function is mediated, at least in part, by CRH action through CRH-R1 on noradrenaline neurons residing in the LC that trigger GnRH discharge and gonadotropin secretion. (Endocrinology 153: 4838-4848, 2012)

Medial amygdaloid nucleus 5-HT2C receptors are involved in the hypophagic effect caused by zimelidine in rats

The medial amygdaloid nucleus (MeA) is a sub-region of the amygdaloid complex that has been described as participating in food intake regulation. Serotonin has been known to play an important role in appetite and food intake regulation. Moreover, serotonin 5-HT2C and 5-HT1A receptors appear to be critical in food intake regulation. We investigated the role of the serotoninergic system in the MeA on feeding behavior regulation in rats. The current study examined the effects on feeding behavior regulation of the serotonin reuptake inhibitor, zimelidine, administered directly into the MeA or given systemically, and the serotoninergic receptors mediating its effect. Our results showed that microinjection of zimelidine (0.2, 2 and 20 nmol/100 nL) into the MeA evoked dose dependent hypophagic effects in fasted rats. The selective 5-HT1A receptor antagonist WAY-100635 (18.5 nmol/100 nL) or the 5-HT1B receptor antagonist SB-216641 microinjected bilaterally into the MeA did not change the hypophagic effect evoked by local MeA zimelidine treatment. However, microinjection of the selective 5-HT2C receptor antagonist SB-242084 (10 nmol/100 nL) was able to block the hypophagic effect of zimelidine. Moreover, microinjection of the 5-HT2C receptor antagonist SB-242084 into the MeA also blocked the hypophagic effect caused by zimelidine administered systemically. These results suggest that MeA 5-HT2C receptors modulate the hypophagic effect caused by local MeA administration as well as by systemic zimelidine administration. Furthermore, 5-HT2C into the MeA could be a potential target for systemic administration of zimelidine. (C) 2012 Elsevier Ltd. All rights reserved.

RefZ Facilitates the Switch from Medial to Polar Division during Spore Formation in Bacillus subtilis

During sporulation, Bacillus subtilis redeploys the division protein FtsZ from midcell to the cell poles, ultimately generating an asymmetric septum. Here, we describe a sporulation-induced protein, RefZ, that facilitates the switch from a medial to a polar FtsZ ring placement. The artificial expression of RefZ during vegetative growth converts FtsZ rings into FtsZ spirals, arcs, and foci, leading to filamentation and lysis. Mutations in FtsZ specifically suppress RefZ-dependent division inhibition, suggesting that RefZ may target FtsZ. During sporulation, cells lacking RefZ are delayed in polar FtsZ ring formation, spending more time in the medial and transition stages of FtsZ ring assembly. A RefZ-green fluorescent protein (GFP) fusion localizes in weak polar foci at the onset of sporulation and as a brighter midcell focus at the time of polar division. RefZ has a TetR DNA binding motif, and point mutations in the putative recognition helix disrupt focus formation and abrogate cell division inhibition. Finally, chromatin immunoprecipitation assays identified sites of RefZ enrichment in the origin region and near the terminus. Collectively, these data support a model in which RefZ helps promote the switch from medial to polar division and is guided by the organization of the chromosome. Models in which RefZ acts as an activator of FtsZ ring assembly near the cell poles or as an inhibitor of the transient medial ring at midcell are discussed.

Fast detection of the magnetic easy axis on steel sheet using the continuous rotational Barkhausen method

The magnetic behaviour of most commercial ferromagnetic steels is usually anisotropic presenting a magnetic easy axis. Changes in the direction of this axis can be related to mechanical changes and anomalies that occur in the fabrication process. The present work describes a method that uses a device with permanent magnets to create a precise rotational magnetic field. The device measures continuous Magnetic Barkhausen Noise signals related to the angle of magnetization, in order to determine the direction of the macroscopic magnetic easy axis. It also offers the possibility of obtaining real time parameters that quantify the magnetic anisotropy of the sample. (C) 2011 Elsevier Ltd. All rights reserved.

The endocannabinoid and endovanilloid systems interact in the rat prelimbic medial prefrontal cortex to control anxiety-like behavior

Cannabinoid receptor 1 (CB1) agonists usually induce dose-dependent biphasic effects on anxiety-related responses. Low doses induce anxiolytic-like effects, whereas high doses are ineffective or anxiogenic, probably due to activation of Transient Receptor Potential Vanilloid Type 1 (TRPV1) channels. In this study we have investigated this hypothesis by verifying the effects of the CB1/TRPV1 agonist ACEA injected into the prelimbic medial prefrontal cortex (PL) and the participation of endocannabinoids in the anxiolytic-like responses induced by TRPV1 antagonism, using the elevated plus-maze (EPM) and the Vogel conflict test (VCT). Moreover, we verified the expression of these receptors in the PL by double labeling immunofluorescence. ACEA induced anxiolytic-like effect in the intermediate dose, which was attenuated by previous injection of AM251, a CB1 receptor antagonist. The higher and ineffective ACEA dose caused anxiogenic- and anxiolytic-like effects, when injected after AM251 or the TRPV1 antagonist 6-iodonordihydrocapsaicin (6-I-CPS), respectively. Higher dose of 6-I-CPS induced anxiolytic-like effects both in the EPM and the VCT, which were prevented by previous administration of AM251. In addition, immunofluorescence showed that CB1 and TRPV1 receptors are closely located in the PL These results indicate that the endocannabinoid and endovanilloid systems interact in the PL to control anxiety-like behavior. (C) 2012 Elsevier Ltd. All rights reserved.

Feasibility of Intralaminar, Lateral Mass, or Pedicle Axis Vertebra Screws in Children Under 10 Years of Age: A Tomographic Study

BACKGROUND: There are several techniques for screw insertion in upper cervical spine surgery, and the use of the 3.5-mm screw is usually the standard. However, there is no consensus regarding the feasibility of using these screws in the pediatric population. OBJECTIVE: To determine the measurement of the lamina angle, lamina and pedicle length and thickness, and lateral mass length of the topographic axial view of the axis vertebra of 2- to 10-year-old children to guide the use of surgical screws. METHODS: Seventy-five computed tomography scans from 24- to 120-month-old patients were studied. Measurements were taken in an axial view of C2 and correlated with 2 age groups and both sexes. Statistical analysis was performed with the Student t test. RESULTS: In the 24- to 48-month age group, only 5.5% of the lamina and 8.3% of the pedicles had thicknesses < 3.5 mm. In the 49- to 120-month age group, there were no lamina thickness values < 3.5 mm, and 1.2% of pedicle thicknesses were < 3.5 mm. Both age groups had no lamina and pedicle lengths < 12 mm and no lateral mass lengths > 12 mm. CONCLUSION: In the majority of cases, the use of 3.5-mm lamina and pedicle screws in children is feasible. A base value of 45 degrees for the spinolaminar angle can be adopted as a reference for insertion of screws in the C2 lamina. This information can be particularly useful for decision making during preoperative planning for C1-C2 or craniocervical arthrodesis in children.

beta-ADRENOCEPTORS IN THE MEDIAL AMYGDALOID NUCLEUS MODULATE THE TACHYCARDIAC RESPONSE TO RESTRAINT STRESS IN RATS

In the present study, we investigated the involvement of beta-adrenoceptors in the medial amygdaloid nucleus (MeA) in cardiovascular responses evoked in rats submitted to an acute restraint stress. We first pretreated Wistar rats with the nonselective beta-adrenoceptor antagonist propranolol microinjected bilaterally into the MeA (10, 15, and 20 nmol/100 nL) 10 min before exposure to acute restraint. The pretreatment with propranolol did not affect the blood pressure (BP) increase evoked by restraint. However, it increased the tachycardiac response caused by acute restraint when animals were pretreated with a dose of 15 nmol, without a significant effect on the BP response. This result indicates that beta-adrenoceptors in the MeA have an inhibitory influence on restraint-evoked heart rate (HR) changes. Pretreatment with the selective beta(2)-adrenoceptor antagonist ICI 118,551 (10, 15, and 20 nmol/100 nL) significantly increased the restraint-evoked tachycardiac response after doses of 15 and 20 nmol, an effect that was similar to that observed after the pretreatment with propranolol at a dose of 15 nmol, without a significant effect on the BP response. Pretreatment of the MeA with the selective beta(1)-adrenoceptor antagonist CGP 20712 (10, 15, and 20 nmol/100 nL) caused an opposite effect on the HR response, and a significant decrease in the restraint-evoked tachycardia was observed only after the dose of 20 nmol, without a significant effect on the BP response. Because propranolol is an equipotent antagonist of both beta(1) and beta(2)-adrenoceptors, and opposite effects were observed after the treatment with the higher doses of the selective antagonists ICI 118,551 and CGP 20712, the narrow window in the dose-response to propranolol could be explained by a functional antagonism resulting from the simultaneous inhibition of beta(1) and beta(2)-adrenoceptors by the treatment with propranolol. The present results suggest that beta(2)-adrenoceptors have an inhibitory influence on the restraint-evoked tachycardiac response, whereas beta(1)-adrenoceptors have a facilitatory influence on the restraint-evoked tachycardiac response. (c) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

TOMOGRAPHIC ANALYSIS OF ANATOMICAL PARAMETERS OF THE AXIS IN CHILDREN

Objective: To carry out an anatomical study of the axis with the use of computed tomography (CT) in children aged from two to ten years, measuring the lamina angle, lamina and pedicle length and thickness, and lateral mass length. Methods: Sixty-four CTs were studied from patients aged 24 to 120 months old, of both sexes and without any cervical anomaly. The measurements obtained were correlated with the data on age and sex of the patients. Statistical analysis was performed using the Students "t" tests. Results: We found that within the age range 24-48 months, 5.5% of the lamina and 8.3% of the pedicles had thicknesses of less than 3.5mm, which is the minimum thickness needed for insertion of the screw. Between 49 and 120 months, there were no lamina thicknesses of less than 3.5mm, and 1.2% of the pedicle thicknesses were less than 3.5mm values. Neither of the age groups had any lamina and pedicle lengths of less than 12mm, or lateral mass lengths greater than 12mm. Conclusion: The analysis of the data obtained demonstrates that most of the time, is possible to use a 3.5mm pedicle screw in the laminas and pedicles of the axis in children. Level of Evidence: II, Development of diagnostic criteria in consecutive patients.

Medial prefrontal cortex endocannabinoid system modulates baroreflex activity through CB1 receptors

Ferreira-Junior NC, Fedoce AG, Alves FHF, Correa FMA, Resstel LBM. Medial prefrontal cortex endocannabinoid system modulates baroreflex activity through CB1 receptors. Am J Physiol Regul Integr Comp Physiol 302: R876-R885, 2012. First published December 28, 2011; doi: 10.1152/ajpregu.00330.2011.-Neural reflex mechanisms, such as the baroreflex, are involved in the regulation of cardiovascular system activity. Previous results from our group (Resstel LB, Correa FM. Medial prefrontal cortex NMDA receptors and nitric oxide modulate the parasympathetic component of the baroreflex. Eur J Neurosci 23: 481-488, 2006) have shown that glutamatergic synapses in the ventral portion of the medial prefrontal cortex (vMPFC) modulate baroreflex activity. Moreover, glutamatergic neurotransmission in the vMPFC can be modulated by the endocannabinoids system (eCBs), particularly the endocannabinoid anandamide, through presynaptic CB1 receptor activation. Therefore, in the present study, we investigated eCBs receptors that are present in the vMPFC, and more specifically whether CB1 receptors modulate baroreflex activity. We found that bilateral microinjection of the CB1 receptor antagonist AM251 (100 or 300 pmol/200 nl) into the vMPFC increased baroreflex activity in unanesthetized rats. Moreover, bilateral microinjection of either the anandamide transporter inhibitor AM404 (100 pmol/200 nl) or the inhibitor of the enzyme fatty acid amide hydrolase that degrades anandamide, URB597 (100 pmol/200 nl), into the MPFC decreased baroreflex activity. Finally, pretreatment of the vMPFC with an ineffective dose of AM251 (10 pmol/200 nl) was able to block baroreflex effects of both AM404 and URB597. Taken together, our results support the view that the eCBs in the vMPFC is involved in the modulation of baroreflex activity through the activation of CB1 receptors, which modulate local glutamate release.

Risk assessment behaviors associated with corticosterone trigger the defense reaction to social isolation in rats: Role of the anterior cingulate cortex

The extent to which the hypothalamic-pituitary-adrenal axis is activated by short-term and long-term consequences of stress is still open to investigation. This study aimed to determine (i) the correlation between plasma corticosterone and exploratory behavior exhibited by rats subjected to the elevated plus maze (EPM) following different periods of social isolation, (ii) the effects of the corticosterone synthesis blocker, metyrapone, on the behavioral consequences of isolation, and (iii) whether corticosterone produces its effects through an action on the anterior cingulate cortex, area 1 (Cg1). Rats were subjected to 30-min, 2-h, 24-h, or 7-day isolation periods before EPM exposure and plasma corticosterone assessments. Isolation for longer periods of time produced greater anxiogenic-like effects on the EPM. However, stretched attend posture (SAP) and plasma corticosterone concentrations were increased significantly after 30 min of isolation. Among all of the behavioral categories measured in the EPM, only SAP positively correlated with plasma corticosterone. Metyrapone injected prior to the 24 h isolation period reversed the anxiogenic effects of isolation. Moreover, corticosterone injected into the Cg1 produced a selective increase in SAP. These findings indicate that risk assessment behavior induced by the action of corticosterone on Cg1 neurons initiates a cascade of defensive responses during exposure to stressors.

TRAUMATIC SPONDYLOLISTHESIS OF THE AXIS: EPIDEMIOLOGY, MANAGEMENT AND OUTCOME

Objective: To evaluate cases of traumatic spondylolisthesis of the axis and describe them in relation to epidemiology, classification, neurological deficit, healing time and treatment method. Method: A retrospective analysis of the medical records of patients treated between 2002 and 2010 at IOT-FMUSP. Inclusion criteria: pars interarticularis fracture of C2. Results: 68% were male patients, with a mean age of 39.1 years. We used the classification by Effendi, modified by Levine-Edwards. Type I fractures were observed in five patients (31.2%) and type II in eight patients (50%). Only three patients (18%) had type IIa fracture. There were no cases of type III. Mechanism: Eight car accidents and four falls. Other mechanisms: being run over, and diving accidents. Treatment with halo traction was used in eleven patients, using minerva cast and halo-cast. Healing time: 3.6 months. Follow-up time: 9.6 months. Discussion: In general, hangman fracture has a good prognosis, which is confirmed by our results. There was no need for surgery in any of the cases. The incidence of neurological deficit is low. No patient had unstable fracture (type III). Conclusion: This paper suggests that traumatic spondylolisthesis of the axis continues to be an injury that is successfully treated by conservative treatment in most cases. Level of Evidence IV, Case series.

The medial amygdaloid nucleus is involved in the cardiovascular pathway activated by noradrenaline into the lateral septal area of rats

We have previously reported that noradrenaline (NA) microinjected into the lateral septal area (LSA) caused pressor and bradicardic responses that were mediated by vasopressin release into the circulation through the paraventricular nucleus of hypothalamus (PVN). Although PVN is the final structure involved in the cardiovascular responses caused by NA in the LSA, there is no evidence of direct connections between these areas, suggesting that some structures could be links in this pathway. In the present study, we verified the effect of reversible synaptic inactivation of the medial amygdaloid nucleus (MeA), bed nucleus of stria terminalis (BNST) or diagonal band of Broca (DBB) with Cobalt Chloride (CoCl2) on the cardiovascular response to NA microinjection into the LSA of unanesthetized rats. Male Wistar rats had guide cannulae implanted into the LSA and the MeA, BNST or DBB for drug administration, and a femoral catheter for blood pressure and heart rate recordings. Local microinjection of CoCl2 (1 mm in 100 nL) into the MeA significantly reduced the pressor and bradycardic responses caused by NA microinjection (21 nmol in 200 nL) into the LSA. In contrast, microinjection of CoCl2 into the BNST or DBB did not change the cardiovascular responses to NA into the LSA. The results indicate that synapses within the MeA, but not in BNST or DBB, are involved in the cardiovascular pathway activated by NA microinjection into the LSA.

alpha 1 and alpha 2-adrenoceptors in the medial amygdaloid nucleus modulate differently the cardiovascular responses to restraint stress in rats

Medial amygdaloid nucleus (MeA) neurotransmission has an inhibitory influence on cardiovascular responses in rats submitted to restraint, which are characterized by both elevated blood pressure (BP) and intense heart rate (HR) increase. In the present study, we investigated the involvement of MeA adrenoceptors in the modulation of cardiovascular responses that are observed during an acute restraint. Male Wistar rats received bilateral microinjections of the selective alpha 1-adrenoceptor antagonist WB4101 (10, 15, and 20 nmol/100 nL) or the selective alpha 2-adrenoceptor antagonist RX821002 (10, 15, and 20 nmol/nL) into the MeA, before the exposure to acute restraint. The injection of WB4101 reduced the restraint-evoked tachycardia. In contrast, the injection of RX821002 increased the tachycardia. Both drugs had no influence on BP increases observed during the acute restraint. Our findings indicate that alpha 1 and alpha 2-adrenoceptors in the MeA play different roles in the modulation of the HR increase evoked by restraint stress in rats. Results suggest that alpha 1-adrenoceptors and alpha 2-adrenoceptors mediate the MeA-related facilitatory and inhibitory influences on restraint-related HR responses, respectively. (C) 2012 Elsevier Ltd. All rights reserved.

Acute heat stress impairs performance parameters and induces mild intestinal enteritis in broiler chickens: Role of acute hypothalamic-pituitary-adrenal axis activation

Studies on the environmental consequences of stress are relevant for economic and animal welfare reasons. We recently reported that long-term heat stressors (31 +/- 1 degrees C and 36 +/- 1 degrees C for 10 h/d) applied to broiler chickens (Gallus gallus domesticus) from d 35 to 42 of life increased serum corticosterone concentrations, decreased performance variables and the macrophage oxidative burst, and produced mild, multifocal acute enteritis. Being cognizant of the relevance of acute heat stress on tropical and subtropical poultry production, we designed the current experiment to analyze, from a neuroimmune perspective, the effects of an acute heat stress (31 +/- 1 degrees C for 10 h on d 35 of life) on serum corticosterone, performance variables, intestinal histology, and peritoneal macrophage activity in chickens. We demonstrated that the acute heat stress increased serum corticosterone concentrations and mortality and decreased food intake, BW gain, and feed conversion (P < 0.05). We did not find changes in the relative weights of the spleen, thymus, and bursa of Fabricius (P > 0.05). Increases in the basal and the Staphylococcus aureus-induced macrophage oxidative bursts and a decrease in the percentage of macrophages performing phagocytosis were also observed. Finally, mild, multifocal acute enteritis, characterized by the increased presence of lymphocytes and plasmocytes within the lamina propria of the jejunum, was also observed. We found that the stress-induced hypothalamic-pituitary-adrenal axis activation was responsible for the negative effects observed on chicken performance and immune function as well as for the changes in the intestinal mucosa. The data presented here corroborate with those presented in other studies in the field of neuroimmunomodulation and open new avenues for the improvement of broiler chicken welfare and production performance.