Impairment of inhibitory cardiopulmonary vagal reflexes in spontaneously hypertensive rats.
The activity of cardiopulmonary reflexes elicited by 5-hydroxytryptamine (5-HT) and phenyldiguanide (PDG) has been examined in anaesthetised 5- and 12-week-old spontaneously hypertensive (SHR) rats. Intravenous injections of 5-HT or PDG elicited dose-dependent bradycardic and hypotensive responses. In the 5-week-old SHR rats the bradycardic and hypotensive responses to 5-HT were smaller than those measured in WKY rats. At 12 weeks, the SHR rats were less sensitive to the bradycardic actions of 5-HT, as well as PDG, although the reduction in cardiopulmonary reflex sensitivity was less pronounced than that observed in the 5-week-old SHR rats. These findings suggest that cardiopulmonary reflexes are impaired in the SHR rat although some amelioration of this phenomenon may occur as hypertension develops.
Verberne
A J
AJ
University of Melbourne, Department of Medicine, Austin Hospital, Heidelberg, Australia.
Young
N A
NA
Louis
W J
WJ
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003971:Diastole; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D008168:Lung / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology*; D011921:Rats, Inbred WKY / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D012146:Rest; D012701:Serotonin / Q000494:pharmacology; D014630:Vagus Nerve / Q000502:physiology
D012701:Serotonin