Contractile responses to electrical field stimulation and ATP in guinea-pig urinary bladder.
1. The responses of guinea-pig urinary bladder smooth muscle to intramuscular nerve stimulation were investigated by isometric tension recording. 2. The nerve mediated contractions, evoked by field stimulation with a stimulus of 0.5 msec duration, a frequency of 15 Hz and a voltage of 50 V, were inhibited by atropine (10(-6) M) and alpha, beta-MeATP (10(-4) M) to about 80% and 20%, respectively, of control. 3. Simultaneous application of atropine (10(-6) M) and alpha, beta-MeATP (10(-4) M) abolished the contraction evoked by selective nerve stimulation. 4. Terodiline (10(-4) M), one of Ca2+ antagonists, inhibited the contraction evoked by both nerve selective stimulation and exogenously applied ATP. 5. Based on these results we suggested that in guinea-pig urinary bladder, ATP was a predominant excitatory transmitter and the nerve-mediated contraction and exogenous ATP were mainly dependent upon Ca2+ influx.
Department of Physiology, Sapporo Medical College, Japan.
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Kura
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Obara
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Yabu
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002082:Butylamines / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000502:physiology*; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation / Q000502:physiology*
D002082:Butylamines; D002121:Calcium Channel Blockers; D018377:Neurotransmitter Agents; C010637:terodiline; D001285:Atropine; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D002118:Calcium