Interaction between Ca/sup + +/-channel antagonists and. cap alpha. /sub 2/-adrenergic receptors in rabbit ileal cell membrane
An interaction between Ca/sup + +/-channel antagonists and the ..cap alpha../sub 2/-adrenergic receptor on active electrolyte transport was demonstrated in rabbit ileum. Clonidine, an ..cap alpha../sub 2/-agonist, stimulated NaCl absorption apparently by Ca/sup + +/-channel antagonism since it inhibited /sup 45/Ca/sup + +/ uptake across the basolateral membrane and decreased total ileal calcium content. This stimulation was inhibited by the Ca/sup + +/-channel antagonists dl- and l-verapamil and cadmium but not by nifedipine. The binding of /sup 3/H-yohimbine, a specific ..cap alpha../sub 2/-adrenergic antagonist, was studied on purified ileal cell membranes using a rapid filtration technique. dl-Verapamil and Cd/sup + +/ inhibited the specific binding of /sup 3/H-yohimbine over the same concentration range in which they affected transport. In contrast, nifedipine had no effect on binding, just as it had no effect on clonidine-stimulated NaCl absorption. These data demonstrate that there is an interaction between Ca/sup + +/-channels and ..cap alpha../sub 2/-adrenergic receptors in ileal basolateral membranes. Some Ca/sup + +/-channel antagonists alter ..cap alpha../sub 2/-adrenergic binding to the receptor and ..cap alpha../sub 2/-agonist binding leads to changes in Ca/sup + +/ entry. A close spatial relationship between the Ca/sup + +/-channel and the ..cap alpha../sub 2/-receptor could explain the data.
- Research Organization:
- Cornell Univ., Ithaca, NY
- OSTI ID:
- 7189618
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; 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
Similar Records
Postsynaptic alpha-adrenoceptors, calcium mobilization and (/sup 3/H), 4-dihydropyridine binding in vascular smooth muscle of rat tail artery
Alpha-2 adrenergic activity of bromocriptine and quinpirole in chicken pineal gland. Effects on melatonin synthesis and ( sup 3 H)rauwolscine binding
Related Subjects
CALCIUM COMPOUNDS
MEMBRANE TRANSPORT
SYMPATHOMIMETICS
RECEPTORS
BIOCHEMICAL REACTION KINETICS
CALCIUM 45
CATIONS
CELL MEMBRANES
RABBITS
SMALL INTESTINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALCIUM ISOTOPES
CELL CONSTITUENTS
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
EVEN-ODD NUCLEI
GASTROINTESTINAL TRACT
INTERMEDIATE MASS NUCLEI
INTESTINES
IONS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques