title: Failure of heart rate response to cardioaccelerator nerve stimulation in Siamese cats.
abstract: Heart rate responses during stimulation of the cardioaccelerator nerves were compared using Siamese and non-Siamese cats. The positive chronotropic responses of Siamese cats during activation of the cardioaccelerator nerves were significantly less than that observed for non-Siamese cats. There were no differences between the two cat populations when vasopressor and chronotropic responses to norepinephrine were cmpared. Comparison of atria from Siamese and non-Siamese cats using histochemical fluorescence indciated that there was a decreased norepinephrine content of the sympathetic nerves innervating the atria of Siamese cats.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats / Q000502:physiology*; D005260:Female; D006325:Heart Atria / Q000294:innervation*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D013045:Species Specificity; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission
chemical_list: D009638:Norepinephrine