Cardiovascular effects of 1-nitro-2-phenylethane, the main constituent of the essential oil of Aniba canelilla, in spontaneously hypertensive rats

• Published in: Fundamental & clinical pharmacology 2011-12, Vol.25 (6), p.661-669
• Main Authors: Interaminense, Leylliane de Fátima Leal, de Siqueira, Rodrigo José Bezerra, Xavier, Fabiano Elias, Duarte, Gloria Pinto, Magalhães, Pedro Jorge Caldas, da Silva, Joyce Kelly, Maia, José Guilherme Soares, Sousa, Pergentino José da Cunha, Leal-Cardoso, José Henrique, Lahlou, Saad
• Format: Article
• Language: English
• Subjects: 1-nitro-2-phenylethane; Animals; Arterial hypertension. Arterial hypotension; Benzene Derivatives - administration & dosage; Benzene Derivatives - isolation & purification; Benzene Derivatives - pharmacology; Biological and medical sciences; Blood and lymphatic vessels; Bradycardia - chemically induced; Cardiology. Vascular system; Dose-Response Relationship, Drug; essential oil of Aniba canelilla; Hypertension - drug therapy; isolated mesenteric preparation; Lauraceae - chemistry; Male; Medical sciences; Mesenteric Artery, Superior - drug effects; Mesenteric Artery, Superior - metabolism; Oils, Volatile - administration & dosage; Oils, Volatile - isolation & purification; Oils, Volatile - pharmacology; Pharmacology. Drug treatments; Rats; Rats, Inbred SHR; Reflex - drug effects; sensory C-fibers; SHR; vago-vagal reflex; Vagus Nerve - drug effects; Vagus Nerve - metabolism; Vasodilation - drug effects
• ISSN: 0767-3981; 1472-8206
• DOI: 10.1111/j.1472-8206.2010.00891.x

This study investigated the cardiovascular responses to the essential oil of Aniba canelilla (EOAC) and its main constituent 1‐nitro‐2‐phenylethane (NP) in spontaneously hypertensive rats (SHRs). In anesthetized SHRs, intravenous (i.v.) bolus injections of EOAC (1–20 mg/kg) or NP (1–10 mg/kg) 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 EOAC and NP both at 10 mg/kg was absent after left ventricle injection, fully abolished by bilateral vagotomy and perineural treatment of both cervical vagus nerves with capsaicin (250 μg/mL) while remained unaltered by i.v. pretreatment with capsazepine (1 mg/kg) or ondansetron (30 μg/kg). In conscious SHRs, NP (5 and 10 mg/kg, i.v.) evoked rapid hypotensive and bradycardiac effects (phase 1) that were fully abolished by methylatropine (1 mg/kg, i.v.) pretreatment. In rat endothelium‐containing mesenteric preparations, increasing concentrations (0.1–1000 μg/mL) of EOAC and NP relaxed the phenylephrine‐induced contraction in a concentration‐dependent manner. It is concluded that NP 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. This effect does not appear to involve activation of either vanilloid TPRV1 or 5‐HT3 receptors located on vagal sensory nerves. The phase 2 hypotensive response to i.v. NP seems to result, at least in part, from its direct vasodilatory effect on the peripheral smooth muscle. All in vivo and in vitro effects of EOAC are mostly attributed to the actions of its main constituent NP.