Adenosine causes contractions in spiral strips and relaxations in transverse strips of guinea-pig trachea: studies on mechanism of action.
Guinea-pig tracheae were cut into transverse strips or spirals and although there is only minor difference in the angle of cut, the former preparations relaxed in response to ATP and adenosine while the latter contracted. Theophylline antagonised both types of response suggesting involvement of P1-purinoceptors. Dipyridamole potentiated inhibitory responses to ATP and adenosine in transverse strips but reversed contractile responses to ATP and adenosine in spiral strips. Antagonism of contractions to ATP and adenosine in spiral strips by hyoscine is consistent with an action of adenosine on cholinergic nerves. The likelihood that ATP rapidly forms adenosine by which it acts is discussed.
D000241:Adenosine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004176:Dipyridamole / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000033:anatomy & histology / Q000187:drug effects*; D013806:Theophylline / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects
D004176:Dipyridamole; D000255:Adenosine Triphosphate; D013806:Theophylline; D000241:Adenosine