Nitrated nonivamide displaying a drawback of proton's role in capsaicin-associated sensory and neuronal activities

Nitrated nonivamide (NVANO)-induced triad hypotension, and biphasic bradyca rdia at 0.25-1.0 mg/kg (IV) was inhibited by capsazepine (1.0 mg/kg, IV), a tropine (1.0 mg/kg, IV), and vagotomy in rats. NVANO also elicited a hypote nsive spinal reflex at 5.0 mg/kg (IA). In the isolated rat vagus, NVANO (10 .0-100.0 mu M) revealed a sensory C-spike inhibition and membrane depolariz ation. NVANO (5.0 mu M)-induced calcium influx in the isolated rat dorsal r oot ganglion cells (DRGs) was diminished by capsazepine (10.0 mu M). In the isolated guinea pig atria, NVANO (1.0-50.0 mu M)-induced positive inotropi c and chronotropic activities were antagonized by capsazepine (1.0-10.0 mu M) and human calcitonin gene-related peptide((8-37)) (hCGRP((8-37)); 0.1-1. 0 mu M). (C) 1999 Elsevier Science Inc. All rights reserved.