PHARMACOLOGICAL CHARACTERIZATION AND TISSUE DISTRIBUTION OF THE HUMANAND RAT GALR1 RECEPTORS

The diverse biological functions of galanin are mediated via membrane bound high-affinity receptors. In order to identify and characterize p otential galanin receptor subtypes, we have examined the specific I-12 5-galanin binding to the CHP-212 human neuroblastoma cell line. The ga lanin receptors expressed in CHP-212 cells, like GALR1 have high affin ity for galanin (Kd = 0.07 nM) and the potency for inhibition of I-125 -galanin binding by galanin peptides parallels that of hGALR1 expresse d in a stable CHO cell line. We confirmed that GALR1 is expressed in t hese cells by RT-PCR. We further determined the tissue expression patt erns of hGALR1 which is expressed in a variety of human tissues at a v ery low level, with the highest levels seen in heart, small intestine and prostate. A species of similar to 70 kDa is recognized by antisera specific for hGALR1 by Western blot analysis and should allow future measurements of receptor protein expression. (C) 1997 Academic Press.