Pertussis toxin and pre-junctional alpha 2-adrenoreceptors in rat heart and vas deferens.
1. The effects of pretreatment with pertussis toxin (50-200 micrograms kg-1, i.p.) on the pre-junctional inhibitory actions of the alpha 2-adrenoreceptor agonist xylazine were examined by employing the pithed rat and rat isolated vas deferens. 2. In pithed rats, pertussis toxin attenuated the pressor response to xylazine, but did not alter the pre-junctional cardio-inhibitory actions of xylazine. In epididymal portions of rat vas deferens, pretreatment with pertussis toxin did not alter the pre-junctional inhibitory action of xylazine. 3. These data lend no support for the view that alpha 2-adrenoreceptor-mediated prejunctional inhibition involves inhibition of adenylate cyclase through the Ni regulatory protein, at least in the tissues examined.
Docherty
J R
JR
Department of Clinical Pharmacology, Royal College of Surgeons, Ireland, Dublin.
D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006321:Heart / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D037342:Pertussis Toxin; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000502:physiology; D014649:Vas Deferens / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*; D014991:Xylazine / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D011942:Receptors, Adrenergic, alpha; D010566:Virulence Factors, Bordetella; D014991:Xylazine; D037342:Pertussis Toxin