Luo X X
Department of Pharmacology, Fourth Military Medical University, Xi'an.
Sheng Li Ke Xue Jin Zhan. 1995 Jul;26(3):233-6.
This is the first time to report the existence of new presynaptic inhibitory autoreceptors--histamine H3-receptors in guinea pig myocardium. We found that (R)-alpha-methylhistamine (alpha-MeHA), a selective histamine H3-receptor agonist, attenuates the sympathetic inotropic response of isolated guinea pig atria elicited by electrical field stimulation. This inhibition was associated with a marked reduction in endogenous norepinephrine release. The above phenomenon was antagonised by selective histamine H3-receptor antagonists, and inhibited by pretreatment with N ethylmeleimide. The cardiac sympathetic response could be attenuated or facilitated by increase or decrease of endogenous histamine. Our findings indicate that the endogenous histamine might be involved in the modulation of cardiac sympathetic neurotransmission by interacting with histamine H3-receptors and the receptors are probably coupled to a G(o)/Gi protein.
这是首次报道豚鼠心肌中存在新的突触前抑制性自身受体——组胺H3受体。我们发现，选择性组胺H3受体激动剂（R）-α-甲基组胺（α-MeHA）可减弱电场刺激诱发的离体豚鼠心房的交感正性肌力反应。这种抑制与内源性去甲肾上腺素释放的显著减少有关。上述现象可被选择性组胺H3受体拮抗剂拮抗，并被N-乙基马来酰亚胺预处理所抑制。内源性组胺的增加或减少可减弱或增强心脏交感反应。我们的研究结果表明，内源性组胺可能通过与组胺H3受体相互作用参与心脏交感神经传递的调节，且这些受体可能与G（o）/Gi蛋白偶联。
