title: Field stimulation of the carotid baroreceptor complex does not compromise baroreceptor function in spontaneously hypertensive rats.
abstract: Field stimulation of the carotid baroreceptors has been successfully used to induce a long-term reduction in blood pressure. However, baroreceptor stimulation may interfere with or compromise the beneficial short-term blood pressure regulation function of the baroreceptors. This study aims to quantify the baroreceptor function before and during acute, unilateral field stimulation of the carotid baroreceptors. Spontaneously Hypertensive Rats (n=7) were anaesthetised and instrumented to measure heart rate and mean arterial pressure (MAP), aortic pulse wave velocity (a surrogate measure of arterial stiffness), abdominal aortic flow and renal artery flow. A custom made field stimulation device was fitted to the left common carotid artery. Baroreceptor function was measured by quantifying heart rate response to MAP change induced by bolus injection of phenylephrine. Field stimulation of the baroreceptors reduced heart rate by 20 bpm (p=0.003) with MAP reduction of 18 mmHg (p=0.008). Maximal barorecep-tor gain without stimulation was -1.20±0.41 bpm/mmHg and during stimulation -1.41±0.52 bpm/mmHg (p=0.59). The MAP at which maximal gain occurred also did not change (152±11, 160±9 mmHg respectively, p=0.22). This study indicates that unilateral field stimulation of the carotid baroreceptor complex, while causing a sustained reduction of arterial pressure, does not alter acute baroreceptor function peak gain.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kouchaki
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Georgakopoulos
authors.forename: Mark
authors.initials: M
authors.lastname: Butlin
authors.forename: Alberto P
authors.initials: AP
authors.lastname: Avolio
mesh_terms: D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D017536:Carotid Artery, Common / Q000502:physiology; D004558:Electric Stimulation; D004562:Electrocardiography; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011311:Pressoreceptors / Q000737:chemistry / Q000378:metabolism*; D063177:Pulse Wave Analysis; D051381:Rats; D011918:Rats, Inbred SHR
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D010656:Phenylephrine