TY - JOUR T1 - 1-Nitro-2-phenylethane, the main constituent of the essential oil of Aniba canelilla, elicits a vago-vagal bradycardiac and depressor reflex in normotensive rats. AU - de Siqueira,Rodrigo José Bezerra, AU - Macedo,Francisco Igor Bulcão, AU - Interaminense,Leylliane de Fátima Leal, AU - Duarte,Gloria Pinto, AU - Magalhães,Pedro Jorge Caldas, AU - Brito,Teresinha Silva, AU - da Silva,Joyce Kelly Rosário, AU - Maia,José Guilherme Soares, AU - Sousa,Pergentino José da Cunha, AU - Leal-Cardoso,José Henrique, AU - Lahlou,Saad, Y1 - 2010/04/18/ PY - 2009/11/27/received PY - 2010/03/06/revised PY - 2010/03/31/accepted PY - 2010/4/22/entrez PY - 2010/4/22/pubmed PY - 2010/9/29/medline SP - 90 EP - 8 JF - European journal of pharmacology JO - Eur J Pharmacol VL - 638 IS - 1-3 N2 - Previously, it was shown that intravenous (i.v.) treatment with the essential oil of Aniba canelilla (EOAC) elicited a hypotensive response that is due to active vascular relaxation rather than to the withdrawal of sympathetic tone. The present study investigated mechanisms underlying the cardiovascular responses to 1-nitro-2-phenylethane, the main constituent of the EOAC. In pentobarbital-anesthetized normotensive rats, 1-nitro-2-phenylethane (1-10mg/kg, i.v.) elicited dose-dependent hypotensive and bradycardiac effects which were characterized in two periods (phases 1 and 2). The first rapid component (phase 1) evoked by 1-nitro-2-phenylethane (10mg/kg) was fully abolished by bilateral vagotomy, perineural treatment of both cervical vagus nerves with capsaicin (250 microg/ml) and was absent after left ventricle injection. However, pretreatment with capsazepine (1mg/kg, i.v.) or ondansetron (30 microg/kg, i.v.) did not alter phase 1 of the cardiovascular responses to 1-nitro-2-phenylethane (10mg/kg, i.v.). In conscious rats, 1-nitro-2-phenylethane (1-10mg/kg, i.v.) evoked rapid hypotensive and bradycardiac (phase 1) effects that were fully abolished by methylatropine (1mg/kg, i.v.). It is concluded that 1-nitro-2-phenylethane induces a vago-vagal bradycardiac and depressor reflex (phase 1) that apparently results from the stimulation of vagal pulmonary rather than cardiac C-fiber afferents. The transduction mechanism of the 1-nitro-2-phenylethane excitation of C-fiber endings is not fully understood and does not appear to involve activation of either Vanilloid TPRV(1) or 5-HT(3) receptors. The phase 2 hypotensive response to 1-nitro-2-phenylethane seems to result, at least in part, from a direct vasodilatory effect since 1-nitro-2-phenylethane (1-300 microg/ml) induced a concentration-dependent reduction of phenylephrine-induced contraction in rat endothelium-containing aorta preparations. SN - 1879-0712 UR - https://www.unboundmedicine.com/medline/citation/20406629/1_Nitro_2_phenylethane_the_main_constituent_of_the_essential_oil_of_Aniba_canelilla_elicits_a_vago_vagal_bradycardiac_and_depressor_reflex_in_normotensive_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014-2999(10)00290-6 DB - PRIME DP - Unbound Medicine ER -