Characterization of the effect of penehyclidine hydrochloride on muscarinic receptor subtypes mediating the contraction of guinea-pig isolated gastrointestinal smooth muscle.
OBJECTIVE
The aim was to characterize the effect of penehyclidine hydrochloride, which mediates the relaxation of guinea-pig isolated gastrointestinal smooth muscle, on muscarinic receptor subtypes.


METHODS
Radioimmune assay was used to determine cAMP levels in isolated guinea-pig gastrointestinal smooth muscle to compare the selective effects of penehyclidine hydrochloride on muscarinic receptor subtypes.


RESULTS
The results indicated that the relaxing effect of penehyclidine hydrochloride on isolated gastrointestinal smooth muscle contraction induced by acetylcholine was stronger than that of atropine (based on PA2 values). In the radioimmune assay, penehyclidine hydrochloride increased the cAMP content in isolated guinea-pig stomach smooth muscle and decreased the cAMP content in isolated guinea-pig intestinal smooth muscle, but the difference was not statistically significant at a dose of 10 mumol/l.


CONCLUSIONS
The results suggest that penehyclidine hydrochloride has little or no effect on M2 receptor subtypes in guinea-pig gastrointestinal smooth muscle.
Xiao
Hong-Tao
HT
Department of Pharmacy, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China. xht927@163.com
Liao
Zhi
Z
Meng
Xian-Min
XM
Yan
Xiao-Yan
XY
Chen
Shu-Jie
SJ
Mo
Zheng-Ji
ZJ
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D005260:Female; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D011812:Quinuclidines / Q000494:pharmacology*; D011869:Radioligand Assay; D043585:Receptor, Muscarinic M2 / Q000037:antagonists & inhibitors / Q000502:physiology*; D043587:Receptor, Muscarinic M3 / Q000037:antagonists & inhibitors / Q000502:physiology*
D011812:Quinuclidines; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; C486140:penehyclidine; D001285:Atropine; D000242:Cyclic AMP; D000109:Acetylcholine