Histamine-sensitive intrinsic cardiac and intrathoracic extracardiac neurons influence cardiodynamics

摘要: Studies were performed to determine whether 1) histamine can modify the spontaneous activity of mammalian intrinsic cardiac neurons in situ, 2) histamine-sensitive exist intrathoracic and extracardiac ganglia that are involved regulation, 3) possess H1 or H2 receptors. (10 microliters; 100 microM), when applied adjacent spontaneously active canine right atrial increased ongoing some them. Histamine, administered into local arterial blood supply these (0.1 ml; microM) not only their but induced augmentation. Cardioaugmentor responses also elicited microliters 0.1 was limited loci within stellate middle cervical connected heart, surgically disconnected heart. Neuronal no longer after administration H1-selective receptor antagonist triprolidine. They unaffected by application H2-selective cimetidine. No augmentation autonomic following timolol (1 mg/kg i.v.) administration. These data indicate histaminergic receptors, directly indirectly activate adrenergic neurons, thereby inducing