Biomaterial Database

Selective desensitization of 5-hydroxytryptamine 2A receptor mediated contraction in guinea pig trachea. 1994

S W Watts, and K W Schenck, and M L Cohen

Department of Pharmacology and Toxicology, Indiana University, Indianapolis 46227.

5-Hydroxytryptamine (serotonin, 5-HT) contracts the guinea pig trachea through stimulation of 5-HT2A receptors, an effect previously reported to rapidly desensitize. The present studies were designed to examine further the putative desensitization to serotonin. In vitro studies investigating functional desensitization of the guinea pig tracheal 5-HT2A receptor documented that 5-HT (3 x 10(-7) M) significantly (50%) but incompletely reduced subsequent tracheal maximal contraction to 5-HT. In contrast, an equieffective concentration of carbamylcholine (3 x 10(-8) M) did not reduce guinea pig tracheal contraction to 5-HT. Furthermore, 5-HT (3 x 10(-7) M) did not diminish tracheal contraction to carbamylcholine. These data indicate that 5-HT can selectively desensitize guinea pig tracheal contraction to 5-HT. In addition, 5-HT-induced contraction but not carbamylcholine-induced contraction in guinea pig trachea declined over time, an effect that was more pronounced at high concentrations of 5-HT (1 x 10(-6) and 1 x 10(-5) M). Inhibitors of mechanisms that oppose contractility to 5-HT (5-HT-induced relaxation, uptake of 5-HT, or metabolism of 5-HT) did not reverse the decline in contraction to 5-HT (1 x 10(-5) M). The decline in 5-HT-induced contraction was most rapid in the guinea pig trachea and less so in the rat jugular vein and rat aorta, two preparations in which 5-HT induced contraction also occurred via activation of 5-HT2A receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D011976	Receptors, Muscarinic	One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.	Muscarinic Acetylcholine Receptors,Muscarinic Receptors,Muscarinic Acetylcholine Receptor,Muscarinic Receptor,Acetylcholine Receptor, Muscarinic,Acetylcholine Receptors, Muscarinic,Receptor, Muscarinic,Receptor, Muscarinic Acetylcholine,Receptors, Muscarinic Acetylcholine
D011985	Receptors, Serotonin	Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.	5-HT Receptor,5-HT Receptors,5-Hydroxytryptamine Receptor,5-Hydroxytryptamine Receptors,Receptors, Tryptamine,Serotonin Receptor,Serotonin Receptors,Tryptamine Receptor,Tryptamine Receptors,Receptors, 5-HT,Receptors, 5-Hydroxytryptamine,5 HT Receptor,5 HT Receptors,5 Hydroxytryptamine Receptor,5 Hydroxytryptamine Receptors,Receptor, 5-HT,Receptor, 5-Hydroxytryptamine,Receptor, Serotonin,Receptor, Tryptamine,Receptors, 5 HT,Receptors, 5 Hydroxytryptamine
D002217	Carbachol	A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.	Carbamylcholine,Carbacholine,Carbamann,Carbamoylcholine,Carbastat,Carbocholine,Carboptic,Doryl,Isopto Carbachol,Jestryl,Miostat,Carbachol, Isopto
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012680	Sensitivity and Specificity	Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)	Specificity,Sensitivity,Specificity and Sensitivity