Ultrasonic vocalization production of preweanling rats: Effects of central and peripheral administration of α2-adrenoceptor agonists

摘要: Abstract Stimulation of α 2 -adrenoceptors increases the ultrasonic vocalization production preweanling rats, however it is not known whether these critical are located peripherally or centrally. In a series three experiments, vocalizations were measured after 11-day-old rats had been administered clonidine 2-[2,6-diethylphenylamino]-2-imidazole (ST-91) either systemically (i.p.) into third ventricle (i.c.v.). These particular -adrenoceptor agonists chosen because lipophilic and enters central nervous system, while ST-91 hydrophilic does readily cross blood–brain barrier. experiment, clonidine- (1 μg, i.c.v.) ST-91-induced (15 systemic injection antagonist yohimbine (0.5 1 mg/kg, i.p.). Results showed that administration both increased whereas peripheral only clonidine, ST-91, vocalizations. results indicate mediating in system. Yohimbine fully attenuated clonidine-induced but partially This pattern may have due to differential selectivity for subtypes (α 2A , 2B 2C ) imidazoline receptors. When combined with past research, present consistent hypothesis centrally component neural system mediates production.