Aug 1, 1975

Analysis of components in a cardiogenic hypertensive chemoreflex

T N JamesF Urthaler


A cardiogenic hypertensive chemoreflex was studied in 38 anesthetized and three unanesthetized dogs. Serotonin (100 mug/ml) injected into either the left atrium or small brancehes of the proximal left coronary artery produced a maximal response, with 96 +/- 18 mm Hg increment in mean aortic pressure within 6 +/- 2 seconds, lasting about 1 min; a later phase of the same hypertension lasted 9 +/- 5 minutes more and could partially be produced with serotonin injected into the thoracic aorta. Injections into the distal left coronary artery produced only the Bezold-Jarisch reflex. Concomitant with the immediate hypertension there were vagal and sympathetic efferent effects in both the sinus node and the atrioventricular (A-V) junction. Either of these effects could be selectively eliminated and the other augmented by direct local perfusion with an appropriate cholinergic (atropine 10 mug/ml) or adrenergic beta-receptor (propranolol 10 mug/ml) blocking agent. Bilateral vagotomy markedly attenuated but did not eliminate the acute hypertension, but it abolished both chronotropic and dromotropic effects. Phentolamine (2 mg/min i.v.) markedly diminished the hypertensive response. Guanethidine or reserpine pretreatment markedly diminished...Continue Reading

  • References19
  • Citations49


Mentioned in this Paper

Sinoatrial Node
Entire Thoracic Aorta
Serotonin Measurement
Cardiovascular System
Diastolic Blood Pressure
Guanethidine Sulfate (2: 1), 14C-Labeled

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