Effects of Anserine on the Renal Sympathetic Nerve Activity and Blood Pressure in Urethane-Anesthetized Rats

Previous studies have demonstrated that central injection ofL-carnosine (β-alynyl-L-histidine), dipeptide synthesized inmammalian muscles, affects renal sympathetic nerve activity(RSNA) and blood pressure (BP) in anesthetized rats. In thepresent study, using urethane-anesthetized rats, we examinedthe dose-dependent effects of intravenous (IV) injection ofvarious doses of anserine, dipeptide of similar structure toL-carnosine, on RSNA, BP and heart rate (HR). We found thatinjection of a low dose of anserine (1 μg) significantly suppressedRSNA, BP and HR. Conversely, a high dose (1000 μg) of anserinesignificantly elevated RSNA, BP and HR. Pretreatment with lateralcerebral ventricular (LCV) injection of thioperamide, ahistaminergic H3-receptor antagonist, eliminated the effects of alow dose of anserine on RSNA, BP and HR. LCV injection ofdiphenhydramine, a histaminergic H1-receptor antagonist,abolished the effects of a high dose of anserine on RSNA, BP andHR. These findings suggest that anserine affects RSNA, BP andHR in a dose-dependent manner, and that the histaminergicnerve may be involved in the dose-different effects of anserine inrats.