5-hydroxytryptamine receptor 1 5-hydroxytryptamine receptor 1A ADRBRL1 Category=gene. Gpcr18 5-HT-1A G-21 protein 5-HT1A ADRB2RL1 serotonin receptor 1A PR:000001161 IUPHARobj:1 A 5-hydroxytryptamine receptor 1 that is a translation product of the human HTR1A gene or a 1:1 ortholog thereof. HTR1A