title: Theophylline does not affect morphine inhibition of the isolated vas deferens.
abstract: 1 Adenosine and morphine both produced an inhibition of the electrically-evoked twitch of the isolated superfused vas deferens of the mouse. 2 Theophylline, 10 or 100 muM, reduced the inhibitory action of adenosine but did not change inhibition by morphine. 3 It is suggested that adenosine release is not a necessary prerequisite for morphine inhibition of transmitter release. It is also suggested that the involvement of adenosine may follow activation only by opiate mu-receptors.
mesh_terms: D000241:Adenosine / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D013806:Theophylline / Q000494:pharmacology*; D014649:Vas Deferens / Q000187:drug effects*
chemical_list: D009020:Morphine; D013806:Theophylline; D000241:Adenosine