Morphometry and morphology of nucleus of the Sertoli and interstitial cells of the tambaqui Colossoma macropomum (Cuvier, 1881) (Pisces: Characidae) during the reproductive cycle

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

Both alpha(1)- and beta(1)-adrenoceptors in the bed nucleus of the stria terminalis are involved in the expression of conditioned contextual fear

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

Bed nucleus of the stria terminalis alpha(1) and alpha(2) adrenoceptors differentially modulate the cardiovascular responses to exercise in rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bed nucleus of the stria terminalis and the cardiovascular responses to chemoreflex activation

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

5-HT1B receptor in the suprachiasmatic nucleus of the common marmoset (Callithrix jacchus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Antihypertensive responses elicited by central moxonidine in rats: Possible role of nitric oxide

In the present study, we investigated the effects of pretreatment with N-G-nitro-L-arginine methyl ester (L-NAME) (nitric oxide synthase inhibitor) injected intravenously (IV) on the hypotension, bradycardia, and vasodilation produced by moxonidine (alpha(2)-adrenergic/imidazoline receptor agonist) injected into the fourth brain ventricle (4th V) in rats submitted to acute hypertension that results from baroreflex blockade by bilateral injections of kynurenic acid (kyn, glutamatergic receptor antagonist) into the nucleus of the solitary tract (NTS) or in normotensive rats. Male Wistar rats (n = 5 to 7/group) anesthetized with IV urethane (1.0 g kg(-1) of body weight) and a-chloralose (60mg kg(-1) of body weight) were used. Bilateral injections of kyn (2.7 nmol 100 nL(-1)) into the NTS increased baseline mean arterial pressure (148 +/- 11 mm Hg, vs. control: 102 +/- 4mm Hg) and baseline heart rate (417 +/- 11 bpm, vs. control: 379 +/- 6 bpm). Moxonidine (20 nmol mu L-1) into the 4th V reduced mean arterial pressure and heart rate to similar levels in rats treated with kyn into the NTS (68 +/- 9 mm Hg and 359 +/- 7 bpm) or in control normotensive rats (66 +/- 7 mm Hg and 362 +/- 8 bpm, respectively). The pretreatment with L-NAME (2 5 mu mol kg-1, IV) attenuated the hypotension produced by moxonidine into the 4th V in rats treated with kyn (104 +/- 6 mm Hg) or in normotensive rats (95 +/- 8 mm Hg), without changing bradycardia. Moxonidine into the 4th V also reduced renal, mesenteric, and hindquarter vascular resistances in rats treated or not with kyn into the NTS and the pretreatment with L-NAME IV reduced these effects of moxonidine. Therefore, these data indicate that nitric oxide mechanisms are involved in hypotension and mesenteric, renal, and hindquarter vasodilation induced by central moxonidine in normotensive and in acute hypertensive rats.

Activation of the serotonergic 5-HT1A receptor in the paraventricular nucleus of the hypothalamus inhibits water intake and increases urinary excretion in water-deprived rats

The paraventricular nucleus (PVN) may be considered as a dynamic mosaic of chemically-specified subgroups of neurons. 5-HT1A is one of the prime receptors identified and there is expressed throughout all magnocellular regions of the PVN. Several reports have demonstrated that a subpopulation of the magnocellular neurons expressing 5-HT1A receptors are oxytocin (OT) neurons and activation of 5-HT1A receptors in the PVN increases the plasma OT. Increasing evidence shows that OT inhibits water intake and increases urinary excretion in rats. The aim of this study was to investigate the role of serotonergic 5-HT1A receptors in the lateral-medial posterior magnocellular region of the PVN in the water intake and diuresis induced by 24 h of water deprivation. Cannulae were implanted in the PVN of rats. 5-HT injections in the PVN reduced water intake and increased urinary excretion. 8-OH-DPAT (a 5-HT1A agonist) injections blocked the water intake and increased urinary output in all the periods of the observation. pMPPF (a 5-HT1A antagonist) injected bilaterally before the 8-OH-DPAT blocked its inhibitory effect on water intake and its diuretic effect. We suggest that antidipsogenic and diuretic responses seem to be mediated via 5-HT1A receptors of the lateral-medial posterior magnocellular region of the PVN in water-deprived rats. (C) 2008 Elsevier B.V. All rights reserved.

Involvement of the intermediate nucleus of the lateral septal area on angiotensin II-induced dipsogenic and pressor responses

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

Antihypertensive effects of central ablations in spontaneously hypertensive rats

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

Commissural NTS lesions enhance the pressor response to central cholinergic and adrenergic activation

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

Ultramorphology of the Digestive Tract of Paratrechina longicornis (Hymenoptera, Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ultrastructure of the ducts of the reproductive tract of males of Melipona bicolor bicolor Lepeletier (Hymenoptera, Apinae, Meliponini)

The present paper describes the ultrastructural features of seminal vesicle, post-vesicular vas deferens and ejaculatory duct of Melipona bicolor bicolor from newly emerged and mature males. Although the results do not show very consistent morphological signs of secretory activity by the epithelium of these organs, lipidic droplets and lamellar granules present in mature males' seminal vesicles and the vacuoles present in post-vesicular vas deferens are probably secretion. Besides, the spermatozoa in the lumen are immersed in a material of characteristic structure, which must be produced in superior regions of the reproductive system of immature males, not studied here. The presence of sperm cells, apparently in cytoplasm vesicles of seminal vesicle and post-vesicular vas deferens, suggests spermiophagy by their epithelium.

Structure and biological activities of eumenine mastoparan-AF (EMP-AF), a new mast cell degranulating peptide in the venom of the solitary wasp (Anterhynchium flavomarginatum micado)

A new mast cell degranulating peptide, eumenine mastoparan-AF (EMP-AF), was isolated from the venom of the solitary wasp Anterhynchium flavomarginatum micado, the most common eumenine wasp found in Japan. The structure was analyzed by FAB-MS/MS together with Edman degradation, which was corroborated by solid-phase synthesis. The sequence of EMP-AF, Ile-Asn-Leu-Leu-Lys-Ile-Ala-Lys-Gly-Ile-lle-Lys-Ser-Leu-NH(2), was similar to that of mastoparan, a mast cell degranulating peptide from a hornet venom; tetradecapeptide with C-terminus amidated and rich in hydrophobic and basic amino acids. In fact, EMP-AF exhibited similar activity to mastoparan in stimulating degranulation from rat peritoneal mast cells and RBL-2H3 cells. It also showed significant hemolytic activity in human erythrocytes. Therefore, this is the first example that a mast cell degranulating peptide is found in the solitary wasp venom. Besides the degranulation and hemolytic activity, EMP-AF also affects on neuromuscular transmission in the lobster walking leg preparation. Three analogs EMP-AF-1 similar to 3 were snythesized and biologically tested together with EMP-AF, resulting in the importance of the C-terminal amide structure for biological activities. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Bombesin affects the central nervous system to produce sodium intake inhibition in rats

Bombesin (BN) elicits in the rat important behavioural modifications, including inhibition of food and of water intake. Recently, it has been observed that the peptide also inhibits the intake of sodium chloride. To stare whether BN possesses a selective antinatriorexic effect or it elicits only an aspecific depression of ingestive behaviour, we studied the effects of this peptide on the intake of sodium, water or sucrose of Wistar rats after injections into the fourth brain ventricle or into selected brain areas involved in the control of sodium intake, containing BN-like peptides and/or their precursors or specific receptors. We observed that: a) BN (100-200 ng/rat) injected into the fourth brain ventricle inhibits not only the intake of 2% NaCl of sodium depleted rats but also that of water and of 5% sucrose; b) BN (5-50 ng/rat) administered into the nucleus of the solitary tract and the medial amygdala does not influence the intake of these fluids and c) BN (5-50 ng/rat) injected into the paraventricular nucleus does not influence the intake of water and 5% sucrose but potently inhibits that of 2% NaCl. We concluded that the inhibitory effect elicited on salt intake by intracranial administration of BN is selective for this behaviour and is not the expression of an aspecific depression of ingestive behaviour. (C) 1998 Elsevier B.V.