Measuring high pressure baroreceptor sensitivity in the rat

作者：Shiry L J; Hamlin R L^*

来源：Journal of Pharmacological and Toxicological Methods, 2011, 64(1): 97-101.

DOI：10.1016/j.vascn.2011.02.001

• Rat
• Baroreceptor
• Homeostasis
• Blood pressure
• Heart rate
• Anesthetic

Introduction: The high pressure baroreceptor reflex rapidly buffers changes in systemic arterial pressure in response to postural changes, altered gravitational conditions, diseases, and pharmacological agents. Drug-induced exaggeration of changes in heart rate and in systemic arterial pressure is a leading cause of adverse events and of patients terminating use of drugs, particularly in the aging population. This paper presents a facile method for monitoring the high pressure baroreceptor reflex in rats, and presents an alternative to quantifying the magnitude of this reflex using 2 dependent variables, heart rate and systemic arterial pressure, rather than merely change in heart rate.
Methods: Twenty-four rats were allocated to 3 groups: group I anesthetized with 100 mg/kg thiopental, group II anesthetized with 2% isoflurane given by inhalation, group III anesthetized with thiopental but pretreated for 2 weeks with 2 mu g/kg aldosterone given SQ bid. After induction to anesthesia, hair was clipped from the ventral aspect of the neck, and petrolatum was applied to the skin to permit an air-tight seal with a glass funnel attached to a source of variable and controllable negative pressure. Systemic arterial pressure, ECG, heart rate, and a force of suction applied to the neck were all recorded continuously.
Results: After baseline recordings, a force of -20 mm Hg was applied for 20 s over the carotid artery. In rats receiving thiopental, the average changes in heart rate and systemic arterial pressure following the application of -20 mm Hg neck suction were 30 +/- 11 bpm and 45 +/- 14 mm Hg, respectively. The ratios of change in heart and change in systemic arterial pressure to application of negative force over the carotid sinus are 1.5 +/- 0.6 bpm/mm Hg and 0.7 +/- 04 mm Hg/mm Hg, respectively. Mean values for heart rate and for mean systemic arterial pressure during baseline and after application of neck suction for 20 s showed little to no decrease (i.e., blunting) in rats anesthetized with isoflurane or pretreated with aldosterone.
Discussion: Thus this methodology was able to detect, in rats, blunting of baroreceptor function for at least 2 perturbations of this important homeostatic control system.

• 出版日期2011-8