The effects of acetylcholine and dopamine on carotid chemosensory activity in the rabbit.

摘要: 1. Intracarotid (I.C.) injection of either acetylcholine (ACh) or dopamine inhibited spontaneous chemosensory activity recorded from the peripheral cut end sinus nerve in anaesthetized rabbit. 2. High doses ACh (greater than equal to 50 micrograms I.C.) evoked a slight increase discharge which preceded inhibition. This excitation was attributable nicotinic action drug since it abolished by mecamylamine. 3. The muscarinic agonist bethanechol chemoreceptor activity, an effect blocked high atropine, as inhibition caused ACh. Dopamine-induced unaffected atropine. 4. Atropine, sufficient abolish vasodepressor ACh, only slightly reduced inhibitory on chemoreceptors. Also, vasodilators sodium nitrite and nitroprusside did not appreciably alter discharge. It seems unlikely, therefore, that response is secondary vascular changes. 5. dopamine, but antagonist alpha-flupenthixol. implies exogenous release. 6. implications results are discussed, particularly with regard possible physiological role modulator carotid activity.