Infusion of metoprolol or propranolol in conscious spontaneously hypertensive rats reduced heart rate and significantly increased renal sympathetic nerve activity.
Does infusion of metoprolol or propranolol alter mean arterial pressure, heart rate, and renal sympathetic nerve activity in conscious spontaneously hypertensive rats?
In spontaneously hypertensive rats, beta-blockers metoprolol and propranolol reduce heart rate but increase renal sympathetic nerve activity, likely due to decreased arterial baroreceptor activity.
1 Mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded in conscious spontaneously hypertensive rats (SHR). 2 Infusion of metoprolol (4 mumol kg-1 h-1) or propranolol (1.5 mumol kg-1 h-1) reduced HR and significantly increased RSNA. 3 Administration of metoprolol caused a sustained decrease of MAP starting in the third hour of infusion. In contrast, administration of propranolol induced a biphasic response in MAP. It is suggested that the increase of RSNA after both beta-adrenoceptor blocking drugs is due to a decrease in arterial baroreceptor activity.
Majcherczyk et al. (1987) studied Hypertension (Spontaneously hypertensive rats). Metoprolol or propranolol was evaluated on Mean arterial pressure, heart rate, and renal sympathetic nerve activity. Infusion of metoprolol or propranolol in conscious spontaneously hypertensive rats reduced heart rate and significantly increased renal sympathetic nerve activity.
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