Effects of carotid chemoreceptor stimulating and depressing agents on internal intercostal muscle activity in the rabbit.
The effects of carotid chemoreceptor stimulating and depressing agents on internal intercostal muscle activity (IIMA) were studied before and after surgical denervation of the carotid sinus nerve (CSN) in the rabbit. An intracarotid injection of 30 micrograms of sodium cyanide (NaCN) during inspiration caused an increase in both IIMA and respiratory rate (RR). In contrast, intracarotid administration of 10 micrograms of dopamine (DA) during inspiration resulted in a decrease in both IIMA and RR. The NaCN- and DA-induced characteristic responses in IIMA were abolished by the section of the CSN. The results indicate that the excitatory and inhibitory responses of IIMA to intracarotid injections of NaCN and DA are mainly mediated through carotid chemoreflexes.
D000818:Animals; D002346:Carotid Sinus / Q000502:physiology*; D002628:Chemoreceptor Cells / Q000502:physiology*; D003714:Denervation; D004298:Dopamine / Q000494:pharmacology; D007366:Intercostal Muscles / Q000187:drug effects / Q000294:innervation*; D011817:Rabbits; D012119:Respiration / Q000187:drug effects; D012966:Sodium Cyanide / Q000494:pharmacology
D012966:Sodium Cyanide; D004298:Dopamine