Effect of adenosine on carotid chemoreceptor activity in the cat.
1 The effects of intracarotid (i.c.) injections or infusions of adenosine on chemoreceptor activity recorded from the peripheral end of a sectioned carotid sinus nerve have been studied in cats anaesthetized with pentobarbitone. 2 Adenosine injections (0.1-100 micrograms) caused a rapid and marked increase of spontaneous chemoreceptor discharge, the intensity, duration and onset of which was dose-dependent. Infusion of adenosine, 50 microgram/min, also evoked an increase in discharge which persisted for the duration of the infusion. 3 Both theophylline (1 mg i.c.) and aminophylline (1 mg i.c.) caused short-lasting decreases in spontaneous discharge but did not prevent the excitatory effect of adenosine. Theophylline increased the excitatory action of adenosine. 4 Naloxone (400 micrograms i.c.) antagonized the depressant effect of morphine on chemoreceptor discharge but not the excitatory action of adenosine. 5 It is concluded that exogenous adenosine can excite the cat carotid chemoreceptors, an effect which is not prevented by theophylline in the doses studied. The physiological significance of the findings is discussed.
D000241:Adenosine / Q000494:pharmacology*; D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D002339:Carotid Arteries / Q000187:drug effects; D002415:Cats; D002628:Chemoreceptor Cells / Q000187:drug effects* / Q000502:physiology; D004594:Electrophysiology; D005260:Female; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology
D000628:Aminophylline; D009270:Naloxone; D013806:Theophylline; D000241:Adenosine