Data/hora: 25/06/2024 05:43:58

Biblioteca(s): | Embrapa Caprinos e Ovinos.
Data corrente: | 08/11/2002
Data da última atualização: | 08/11/2002
Autoria: | FERREIRA, S. A.; HILEMAN, S. M.; KUEHL, D. E.; JACKSON, G. L.
Título: | Effects of dialyzing y-aminobutyric acid receptor antogonists into the medial preoptic and arcuate ventromedial region on luteinizing hormone release in male sheep.
Ano de publicação: | 1998
Fonte/Imprenta: | Biology of Reproduction, v. 58, n. 4, p.1038-1046, 1998.
Idioma: | Inglês
Conteúdo: | We investigated the effects of microdialyzing y-aminobutyric acid (GABA) receptor antagonists into either the medial preoptic area (mPOA) or the arcuate-ventromedial region (ARC-VMR) on LH secretion. Bicuculline methiodide (BMI, GABAA receptor antagonist), and either 2-hydroxysaclofen (SAC) or CGP 55845A (CGP, GABAA receptor antagonists) were used. In experiment 1, castrated rams received 4-h dialysis into either the mPOA (n = 5) or ARC-VMR (n = 4) of artificial cerebrospinal fluid (aCSF) followed by 4 h of either BMI (aCSF-BMI, 375 uM in mPOA, 1 mM in lhe ARC-VMR for 2-1/2 h), or aCSF-SAC (5 mM). In experiment 2, castrated rams received dialysis only in lhe ARC- VMR (n = 5) of aCSF-aCSF, aCSF-BMI (375 uM), pr aCSF-CGP (50 ~M). In experiment 3, untreated or testosterone (T)-treated castrated rams (n = 6/group) received dialysis only in the ARCVMR of aCSF-aCSF, aCSF-BMI (375 ~M), or aCSF-CGP (500 ~M). Jugular blood was collected at 10-min intervals. In experiment 1, BMI suppressed mean plasma LH (p < 0.05) and increased interpulse interval (IPI, p < 0.05) at both sites. In experiment 2, BMI significantly reduced mean LH and increased IPI (p < 0.01). In experiment 3, BMI reduced mean LH in both lhe presence (p < 0.05) and absence of T (p < 0.01) and in- creased IPI (p < 0.01) in lhe absence of T. SAC, CGP, and aCSF did not affect LH in any experiment. These results show that dialysis of BMI, into either lhe mPOA or lhe ARC-VMR of either castrated or T-treated castrated rams decreased LH release, whereas dialysis of GABAu antagonists at these sites was without detectable effect.
Palavras-Chave: | Endrocrinologia; LH; Receptor.
Thesagro: | Hormônio; Ovino; Reprodução Animal.
Categoria do assunto: | --
Registro original: | Embrapa Caprinos e Ovinos (CNPC)
Exemplares: | CNPC - (15090-1) - ADC - AP - -- -  -  - v.58, n.4 - DIS