Effects of Dihydro‐β‐Erythroidine on the Cat Carotid Chemoreceptors

Abstract

The effects of the nicotinic-blocking drug dlhydro-/3-erythroldine (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 rcductioni 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 rcsponses to NaCN land CO,. findings which are comp-atible witlh cndogenouls ACh exerting an inlhibitory influenice on the chemoreceptors.Conflicting evidence and controversy surround the effects of nicotinic antagonists on the responsiveness of carotid chemoreceptors to physiological stimuli and sodium cyanide [e.g. see Landgren, Liljestrand