Characterization of GABAB receptor in the human colon.

Characterization of the GABA(B) receptor in the human colon was performed by the reverse transcription-polymerase chain reaction (RT-PCR). mRNAs for both subunits of the GABA(B) receptor, GABA(B1) and GABA(B2), were detected in the human colon. The GABA(B1(e)) isoform was detected in the human colon, but not in the brain, and the other isoforms, except GABA(B1(d)), were detected in both tissues. Thus, the GABA(B) receptor may be present as a heterodimer with subunits of GABA(B1) and GABA(B2) in the human colon.