PREDOMINANT EXPRESSION OF SEROTONIN 5-HT1B RECEPTOR MESSENGER-RNA IN PIG CORONARY-ARTERY

Partial cloning of a pig 5-HT1B and pig 5-HT1D receptor was obtained b y PCR using pig genomic DNA as a template. The partial receptor sequen ces show 95 to 97% amino acid identity with their human homologues. A conserved threonine residue is present as the seventh amino acid in tr ansmembrane domain VII for both receptor subtypes. This structural fea ture imparts a non-rodent 5-HT1B receptor pharmacology for the pig 5-H T1B receptor. Reverse-transcription-PCR of poly(A(+)) RNA combined wit h Southern blotting identified specific transcripts for both 5-HT1B an d 5-HT1D receptors in pig coronary artery, although the 5-HT1B recepto r mRNA was predominant.