Serotonin 5-HT1A and 5-HT1B receptors co-mediate the RU 24629-induced locomotor activity of male and female preweanling rats

Publication date: Available online 17 January 2020Source: Pharmacology Biochemistry and BehaviorAuthor(s): Sanders A. McDougall, Jasmine A.M. Robinson, Esperanza Larios Ramirez, Henry A. DiazAbstractThe serotonin (5-HT) 1A/1B agonist RU 24969 robustly increases the locomotor activity of adult male rats and mice; however, studies using selective antagonists alternately report that 5-HT1A, 5-HT1B, or both receptor types mediate RU 24969's locomotor activating effects. The purpose of the present study was to extend these past findings by administering a selective 5-HT1 agonist and/or antagonists to male and female preweanling rats. This age group was tested because younger rats often exhibit psychopharmacological responses that are quantitatively or qualitatively different from adult rats. In a series of experiments, male and female preweanling rats were pretreated with vehicle, the 5-HT1A antagonist WAY 100635 (0.5, 1, 5, or 10 mg/kg), or the 5-HT1B antagonists NAS-181 (5 or 10 mg/kg) or SB 216641 (5 or 10 mg/kg) 30 min before assessment of locomotor activity. Rats were injected with saline or RU 24969 immediately prior to testing. Results showed that RU 24969 (0.625, 1.25, 2.5, or 5 mg/kg) significantly increased the locomotor activity of both male and female preweanling rats (no sex differences were apparent). Antagonism of either the 5-HT1A or the 5-HT1B receptor was sufficient to significantly reduce the locomotor activity of RU 24969-treated preweanling rats. Une...
Source: Pharmacology Biochemistry and Behavior - Category: Biochemistry Source Type: research