title: Effect of alpha-chymotrypsin on the nonadrenergic, noncholinergic contraction of the rat urinary bladder in vitro.
abstract: The role of peptides in mediating the nonadrenergic, noncholinergic (NANC) response of the rat urinary bladder was studied. Electrical stimulation of muscle strips from 3-month-old female Wistar rat urinary bladders in the presence of autonomic blockers (atropine 10(-6) mol/l, propanolol 10(-6) mol/l, phentolamine 10(-6) mol/l, and guanethidine 10(-6) mol/l) showed NANC contraction accounting for 60% of the maximum contractile responses at 40 Hz. Frequency-response studies showed that in the presence of alpha-chymotrypsin (2 U/ml, 30-min incubation), the NANC contractile responses to electrical stimulation at lower frequencies (3-10 Hz) were enhanced (p < 0.05; n = 9). However, no significant differences were observed at higher frequencies (20-40 Hz). With repetitive 4-Hz stimulation, alpha chymotrypsin caused a 19% increase in the NANC contractile response (p < 0.05; n = 8). It is postulated that the NANC response of the rat bladder smooth muscle is composed of an excitatory (contractile) and an inhibitory (relaxant) component. Some peptide(s) is/are responsible for mediating the inhibitory response.
authors.affiliation: Department of Urology, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.
authors.forename: Y C
authors.initials: YC
authors.lastname: Tong
authors.forename: Y C
authors.initials: YC
authors.lastname: Hung
authors.forename: S N
authors.initials: SN
authors.lastname: Lin
authors.forename: J T
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects*; D002918:Chymotrypsin / Q000494:pharmacology*; D004558:Electric Stimulation; D005260:Female; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000187:drug effects* / Q000294:innervation; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects* / Q000294:innervation
chemical_list: D013373:Substance P; D013779:Tetrodotoxin; D002918:Chymotrypsin; D000109:Acetylcholine