Donoso A O, Zárate M B
Brain Res Bull. 1981 Oct;7(4):359-64. doi: 10.1016/0361-9230(81)90029-0.
GABA and gamma-acetylenic-GABA (GAG), a GABA-Transaminase inhibitor, were used in this study to determine the influence of GABA on the release of prolactin. In unrestrained male rats, intraventricular (IVT) injection of GABA in high doses (500 microgram) markedly increased plasma prolactin levels. On the contrary, GABA at low doses (10 microgram) and GAG (100 microgram, IVT), were non effective. Systemic. GABA administration (25,50,100 and 200 mg/kg IP) lacked action. Both IVT and systemic GAG (100 mg/kg) slightly decreased plasma prolactin levels. The stimulation of prolactin release by histamine was prevented, and the proestrus prolactin surge was blunted by GAG injected IP (100 mg/kg at 1300 hr) or IVT (100 microgram). GABA (500 microgram, IVT) exhibited a similar action on the histamine response. Results suggest that GABA in basal condition has a pharmacological ability to increase prolactin release. In contrast, the parallel inhibitory effects of GABA and GAG on the histamine effect, and on the proestrus prolactin surge give evidence in favor of a physiological inhibitory role of GABA in the control of prolactin. GABA might act in these conditions as a modulatory transmitter.
γ-氨基丁酸（GABA）和γ-乙炔基-γ-氨基丁酸（GAG，一种GABA转氨酶抑制剂）被用于本研究，以确定GABA对催乳素释放的影响。在未束缚的雄性大鼠中，脑室内（IVT）注射高剂量（500微克）的GABA可显著提高血浆催乳素水平。相反，低剂量（10微克）的GABA和GAG（100微克，IVT）无效。全身性给予GABA（25、50、100和200毫克/千克，腹腔注射）无作用。IVT和全身性给予GAG（100毫克/千克）均可使血浆催乳素水平略有下降。组胺对催乳素释放的刺激作用被阻断，并且通过腹腔注射（13:00时100毫克/千克）或脑室内注射（100微克）GAG可使动情前期催乳素高峰减弱。GABA（500微克，IVT）对组胺反应表现出类似作用。结果表明，基础状态下的GABA具有增加催乳素释放的药理能力。相反，GABA和GAG对组胺作用以及动情前期催乳素高峰的平行抑制作用证明了GABA在催乳素调控中具有生理抑制作用。在这些情况下，GABA可能作为一种调节性神经递质发挥作用。
