Effects of dihydro-beta-erythroidine on the cat carotid chemoreceptors

The effects of the nicotinic-blocking drug dihydro-beta-erythroidine (DHE) on chemoreceptor responses to physiological and pharmacological stimuli have been examined in pentobarbitone anaesthetized cats in which chemoreceptor discharge was recorded from the peripheral end of a sectioned sinus nerve. High doses of DHE greatly reduced the excitatory action of ACh on the chemoreceptors and caused a reduction in responses to CO2. The effect of NaCN was not much affected even though the high doses of DHE can reasonably be expected to have penetrated the carotid body tissues very effectively. Low doses of DHE reduced the excitatory action of ACh but potentiated responses to NaCN and CO2, findings which are compatible with endogenous ACh exerting an inhibitory influence on the chemoreceptors.