Identification of 5HT/sub 2/-receptors on longitudinal muscle of the guinea pig ileum

Journal Article · Sun Jan 01 04:00:00 EST 1984 · J. Receptor Res.; (United States)

DOI:https://doi.org/10.3109/10799898409042543· OSTI ID:5612593

Engel, G; Hoyer, D; Kalkman, H O; Wick, M B

In binding experiments with the radioligands (/sup 3/H)Ketanserin (HKet) and (/sup 125/I)LSD (ILSD) 21 compounds were investigated using rat brain cortex membranes. The pK/sub D/-values of the compounds were virtually independent of the radioligand used and their rank order was consistent with classification of the binding sites as being of the 5-HT/sub 2/-type. In contrast, in the longitudinal muscle of the guinea pig ileum in the presence of 0.3 microM cinanserin, ILSD labelled sites which were quite different to those in the cortex. In a functional test antagonism of the 5HT induced contraction of the guinea-pig ileum was measured in the presence of 1 microM atropine. The pharmacological inhibition constants (IC/sub 50/-values) of 8 compounds correlated well with the dissociation constants for HKet binding in the cortex and did not correlate with the data from ILSD binding in the guinea pig ileum. It is concluded that the ileum contains postjunctional 5HT/sub 2/-receptors which mediate contraction. The nature of the ILSD binding sites in the ileum remains to be elucidated.

• Research Organization: SANDOZ Ltd., Basle, Switzerland
• OSTI ID: 5612593
• Journal Information: J. Receptor Res.; (United States), Journal Name: J. Receptor Res.; (United States) Vol. 4:1-6; ISSN JRERD
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALOIDS
AMINES
ANIMALS
AROMATICS
ATROPINE
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
AZOLES
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
CEREBRAL CORTEX
CEREBRUM
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GASTROINTESTINAL TRACT
GUINEA PIGS
HALLUCINOGENS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INDOLES
INTERMEDIATE MASS NUCLEI
INTESTINES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PSYCHOTROPIC DRUGS
PYRROLES
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
REACTION KINETICS
RECEPTORS
RODENTS
SEROTONIN
SMALL INTESTINE
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TRYPTAMINES
VERTEBRATES