Miñano F J, Sancibrian M, Serrano J S
Departamento de Farmacologia y Terapéutica, Facultad de Medicina, Universidad de Sevilla, Spain.
J Pharm Pharmacol. 1987 Sep;39(9):721-6. doi: 10.1111/j.2042-7158.1987.tb06976.x.
gamma-Aminobutyric acid (GABA) intraperitoneally injected (i.p.) produced a dose-dependent hypothermia in restrained rats. GABA-induced hypothermia (1000 mg kg-1) was antagonized by pretreatment with atropine (2.5 and 10 mg kg-1 i.p.), hyoscine butylbromide (2.5 mg kg-1 i.p.), hexamethonium (0.75 mg kg-1 i.p.) or physostigmine (0.2 mg kg-1 s.c.). Hexamethonium (7.5 mg kg-1 i.p.) did not influence the hypothermia induced by GABA. The antagonism by physostigmine of GABA-induced hypothermia was attenuated by pretreatment of the rats with either alpha-methyl-p-tyrosine (200 mg kg-1 i.p.) or hexamethonium (7.5 mg kg-1 i.p.), but it was potentiated by either atropine (5 mg kg-1 i.p.) or hexamethonium (0.75 mg kg-1 i.p.). The data indicate that GABA-induced hypothermia may be partly mediated by acetylcholine release. Muscarinic receptors may play an important role in the effect of GABA. The results support the hypothesis of nicotinic presynaptic receptors modulating noradrenergic nerve endings that play a part in the hypothermic response of GABA.
腹腔注射γ-氨基丁酸（GABA）可使束缚状态下的大鼠体温呈剂量依赖性降低。GABA诱导的体温降低（1000 mg·kg⁻¹）可被预先注射阿托品（2.5和10 mg·kg⁻¹，腹腔注射）、丁溴东莨菪碱（2.5 mg·kg⁻¹，腹腔注射）、六甲铵（0.75 mg·kg⁻¹，腹腔注射）或毒扁豆碱（0.2 mg·kg⁻¹，皮下注射）所拮抗。六甲铵（7.5 mg·kg⁻¹，腹腔注射）不影响GABA诱导的体温降低。预先给大鼠注射α-甲基对酪氨酸（200 mg·kg⁻¹，腹腔注射）或六甲铵（7.5 mg·kg⁻¹，腹腔注射）可减弱毒扁豆碱对GABA诱导体温降低的拮抗作用，但预先注射阿托品（5 mg·kg⁻¹，腹腔注射）或六甲铵（0.75 mg·kg⁻¹，腹腔注射）则可增强该拮抗作用。数据表明，GABA诱导的体温降低可能部分由乙酰胆碱释放介导。毒蕈碱受体可能在GABA的作用中起重要作用。结果支持烟碱型突触前受体调节去甲肾上腺素能神经末梢参与GABA体温降低反应的假说。
