title: Pharmacological evidence of α2-adrenergic receptors in the hypotensive effect of Platonia insignis mart.
abstract: Platonia insignis Mart. (Clusiaceae) is a medicinal plant from the Brazilian Amazon region. The present study evaluated the biological potential of the ethanol extract (Pi-EtOH) and ethyl acetate fraction (Pi-EtOAc) of the P. insignis fruit shells on the cardiovascular system of rats. Pi-EtOH or Pi-EtOAc (12.5, 25, and 50 mg/kg) was administered intravenously in normotensive rats (260-300 g), and the mean arterial pressure and the heart rate were monitored. The Pi-EtOH induced hypotension (-11.56±0.89, -7.43±0.85, and -17.56±1.97 mmHg) followed by bradycardia in two highest doses (-8.89±3.62 and -15.79±1.83 beats/min) and Pi-EtOAc, at the same doses, induced hypotension (-11.2±1.03, -14.48±1.13, -29.89±2.67 mmHg) more intensively, followed by tachycardia at the dose 12.5 and 25 mg/kg (15.64±2.06, 19.31±1.92 beats/min) and bradycardia at a dose of 50 mg/kg (-9.98±7.33 beats/min). The hypotensive response from Pi-EtOAc was not attenuated when used in the pretreatment with L-NAME, verapamil, propranolol, and hexamethonium. However, when using yohimbine, the hypotensive effect was inhibited (-4.42±1.28 (P<.05), -3.29±0.99 (P<.05), 2.06±1.18 mmHg (P<.05); Student's t-test). Hence, the Pi-EtOAc seems to act similarly to the α2-adrenergic agonist in this hypotensive effect.
authors: 1 Medicinal Plants Research Center, Federal University of Piauí , Teresina, Brazil .
authors: Marcelo Bezerra
authors: MB
authors: Mendes
authors: José Couras
authors: JC
authors: da Silva-Filho
authors: Carla Kelly Barroso
authors: CK
authors: Sabino
authors: Daniel Dias Rufino
authors: DD
authors: Arcanjo
authors: Cleyton Marcos Melo
authors: CM
authors: Sousa
authors: Isabella Cristhina Gonçalves
authors: IC
authors: Costa
authors: Mariana Helena
authors: MH
authors: Chaves
authors: Rita de Cássia Meneses
authors: Rde C
authors: Oliveira
authors: Aldeídia P
authors: AP
authors: Oliveira
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects; D028084:Clusiaceae / Q000737:chemistry*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D018341:Receptors, Adrenergic, alpha-2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D000959:Antihypertensive Agents; D010936:Plant Extracts; D018341:Receptors, Adrenergic, alpha-2
keywords: Platonia insignis; blood pressure; cardiovascular; hypotension; yohimbine