Molecular identification of ghrelin receptor (GHS-R1a) and its functional role in the gastrointestinal tract of the guinea-pig

► Growth hormone secretagogue receptor1a (GHS-R1a) was identified in guinea-pig brain cDNA and compared with that of other animals. ► Guinea-pig GHS-R1a expressed in HEK 293 cells responded to ghrelin, GHRP-6 and hexarelin in a concentration-dependent manner. ► GHS-R1a mRNA expression was high in the pituitary and hypothalamus, but very low in the gastrointestinal tract. ► Ghrelin was ineffective in producing responses in the stomach and colon but caused slight contraction in the small intestine. ► Functional roles of ghrelin and peripheral GHS-R1a for regulation of gastrointestinal motility are weak in guinea-pigs compared with other animal species.