Unique serotonin receptor (5HT-1C) in choroid plexus is linked to phosphoinositide hydrolysis
The binding of /sup 125/I-LSD to the 5HT-1C site and of /sup 3/H-ket-anserin to the 5HT-2 site was determined in choroid plexus and cerebral cortex of male Sprague-Dawley rats, respectively. As an index of phosphoinositide (PI) hydrolysis, whole choroid plexus and cerebral cortex slices were prelabelled with /sup 3/H-inositol and serotonin (5HT) stimulated release of /sup 3/H-inositol-1-phosphate was measured. 5HT stimulated PI hydrolysis in choroid plexus (6-fold) and in cerebral cortex (2.5-fold). 5HT was more potent in choroid plexus (EC/sub 50/ = 46 nM) consistent with the involvement of the 5HT-1C site. 5HT antagonists, ketanserin, mianserin and spiperone, inhibited the response to 5HT with different potencies in the two tissues. In cerebral cortex all 3 antagonists had nM affinities and a rank order (spiperone > ketanserin > mianserin) consistent with the 5HT-2 site. In choroid plexus, however, the rank order (mianserin > ketanserin > spiperone) and absolute potencies agreed with binding to the 5HT-1C site. These data suggest that the 5HT-1C site is a functional receptor which utilizes PI hydrolysis as its biochemical effector system.
- Research Organization:
- Vanderbilt Univ. School of Medicine, Nashville, TN
- OSTI ID:
- 5508060
- Report Number(s):
- CONF-8604222-; TRN: 86-026628
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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550201* - Biochemistry- Tracer Techniques