Arancibia S, Lyonnet D, Roussel J P, Ixart G, Astier H
Laboratory of Endocrinological Neurobiology, URA 1197 of CNRS, University of Montpellier, France.
Neurosci Lett. 1995 Feb 9;185(2):139-43. doi: 10.1016/0304-3940(95)11245-r.
This work was undertaken to investigate whether the inhibitory tone exerted by GABA on somatostatin (SRIH) release operates in the control of thyrotropin (TSH) secretion in both basal and cold-stimulated conditions. In a first group of animals (G1) undergoing both carotid and third ventricle push-pull cannulation, i.vt. injection of picrotoxin (10(-5) M) induces a significant decrease in plasma TSH level under basal conditions (0.09 +/- 0.02 versus 0.27 +/- 0.4 ng/100 microliters; P < 0.03, n = 5). In a median eminence (ME) push-pull cannulated group of rats (G2), picrotoxin, peripherally administered, blocks cold-induced inhibition of SRIH release (35.0 +/- 1.8 versus 7.4 +/- 3.3 pg/15 min; P < 0.005; n = 5). In a third group of intact rats (G3), peripheral administration of picrotoxin (2 mg/kg i.p.) blunts the cold-induced TSH release (0.17 +/- 0.03 versus 0.46 +/- 0.04 ng/100 microliters; P < 0.001; n = 5). Our results strongly suggest that a decrease in SRIH release is involved in the GABAergic control of basal and cold-induced TSH secretion.
本研究旨在探讨γ-氨基丁酸（GABA）对生长抑素（SRIH）释放的抑制作用是否在基础状态和冷刺激条件下对促甲状腺激素（TSH）分泌的控制中发挥作用。在第一组同时进行颈动脉和第三脑室推挽式插管的动物（G1）中，静脉注射印防己毒素（10^(-5) M）可使基础状态下血浆TSH水平显著降低（0.09±0.02对0.27±0.4 ng/100微升；P<0.03，n=5）。在中隆起（ME）推挽式插管的大鼠组（G2）中，外周给予印防己毒素可阻断冷诱导的SRIH释放抑制（35.0±1.8对7.4±3.3 pg/15分钟；P<0.005；n=5）。在第三组完整大鼠（G3）中，外周给予印防己毒素（2 mg/kg腹腔注射）可减弱冷诱导的TSH释放（0.17±0.03对0.46±0.04 ng/100微升；P<0.001；n=5）。我们的结果强烈表明，SRIH释放的减少参与了基础状态和冷诱导的TSH分泌的GABA能控制。
