L-Carnosine's dose-dependent effects on muscle sympathetic nerves and blood flow

L-Camosine is synthesized in mammalian muscles and brain and affects autonomic neurotransmission and physiological phenomena. To clarify the role of L-carnosine, the effects of intraduodenal administration of L-camosine on muscle sympathetic nerve activity (muscle-SNA) and blood flow (BF) were examined. The changes in muscle-SNA and BF were examined using electrophysiological and Doppler flowmeter in urethane-anesthetized rats. The effect of propranolol, a p-adrenergic antagonist, on the increase in muscle BF due to L-carnosine was also examined. Low dose (111g/300 g body weight lbw]) of L-carnosine increased both muscle-SNA and muscle BF, while high dese (100 mg/300 g bw) of L-camosine decreased both muscle-SNA and muscle BF. Furthermore, propranolol eliminated the increase in muscle BF caused by a low dose of L-carnosine. These results suggest that L-carnosine has dose-dependent effects on muscle BF via changes in muscle-SNA, and the p-adrenergic receptor is implicated in the increase in muscle BF due to L-carnosine. 2015 Elsevier Ireland Ltd. All rights reserved.