Inhibition of sympathetic neurotransmission via NEM-sensitive H3-receptors in the guinea pig vas deferens.
The influence of N-ethylmaleimide (NEM) on sympathetic neurotransmission induced by field stimulation on the isolated guinea pig vas deferens was studied. Application of (R)-alpha-methylhistamine (0.1 mcmol/l) significantly inhibited the sympathetic response by 26.0%, while thioperamide facilitated the sympathetic contraction of vas deferens evoked by field pulses by 221.1%. Pretreatment of vas deferens with NEM (60 mcmol/l) for 15 min abolished both the inhibitory and facilitatory effects. Attenuation of thioperamide facilitatory effect by NEM was not significantly altered when the H3-receptors were occupied by thioperamide prior to and during NEM treatment. The results suggest that effects mediated by H3-receptors in the guinea pig vas deferens were NEM-sensitive and possibly transmitted by Gi or Go proteins.
Luo
X X
XX
Department of Pharmacology, Fourth Military Medical University, Xian, P.R. China.
Song
L
L
Jiang
Y P
YP
Tan
Y H
YH
D000818:Animals; D004558:Electric Stimulation; D005033:Ethylmaleimide / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000276:immunology / Q000378:metabolism; D006168:Guinea Pigs; D017442:Histamine Agonists / Q000494:pharmacology; D006633:Histamine Antagonists; D066298:In Vitro Techniques; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation*; D010880:Piperidines / Q000494:pharmacology; D018100:Receptors, Histamine H3 / Q000187:drug effects*; D017661:Receptors, Presynaptic / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D014649:Vas Deferens / Q000187:drug effects / Q000294:innervation
D017442:Histamine Agonists; D006633:Histamine Antagonists; D008761:Methylhistamines; D010880:Piperidines; D018100:Receptors, Histamine H3; D017661:Receptors, Presynaptic; C069357:alpha-methylhistamine; D019204:GTP-Binding Proteins; C052075:thioperamide; D005033:Ethylmaleimide