title: 5-HT(2A) receptors: location and functional analysis in intestines of wild-type and 5-HT(2A) knockout mice.
abstract: The distribution and function of the 5-hydroxytryptamine (5-HT(2A)) receptor were investigated in the intestines of wild-type (5-HT(2A) +/+) and knockout (5-HT(2A) -/-) mice. In 5-HT(2A) +/+ mice, rats, and guinea pigs, 5-HT(2A) receptor immunoreactivity was found on circular and longitudinal smooth muscle cells, neurons, enterocytes, and Paneth cells. Muscular 5-HT(2A) receptors were concentrated in caveolae; neuronal 5-HT(2A) receptors were found intracellularly and on the plasma membranes of nerve cell bodies and axons. Neuronal 5-HT(2A) immunoreactivity was detected as early as E14 in ganglia, intravillus nerves, and the deep muscle plexus. The 5-HT(2A) -/- colon did not express 5-HT(2A) receptors and did not contract in response to exogenous 5-HT. 5-HT(2A) -/- enterocytes were smaller, Paneth cells fewer, and muscle layers thinner (and showed degeneration) compared with those of 5-HT(2A) +/+ littermates. The 5-HT(2A) receptor may thus be required for the maintenance and/or development of enteric neuroeffectors and other enteric functions, although gastrointestinal and colonic transit times in 5-HT(2A) -/- and +/+ mice did not differ significantly.
authors.affiliation: Department of Anatomy and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA. ef7@columbia.edu
authors.forename: Elena
authors.initials: E
authors.lastname: Fiorica-Howells
authors.forename: Rene
authors.initials: R
authors.lastname: Hen
authors.forename: Jay
authors.initials: J
authors.lastname: Gingrich
authors.forename: Zhishan
authors.initials: Z
authors.lastname: Li
authors.forename: Michael D
authors.initials: MD
authors.lastname: Gershon
mesh_terms: D000818:Animals; D020895:Enterocytes / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D005333:Fetus / Q000166:cytology; D005746:Gastric Emptying / Q000502:physiology; D005769:Gastrointestinal Motility / Q000502:physiology; D007150:Immunohistochemistry; D007422:Intestines / Q000737:chemistry* / Q000294:innervation / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016253:Microscopy, Immunoelectron; D009130:Muscle, Smooth / Q000737:chemistry / Q000294:innervation / Q000473:pathology; D009197:Myenteric Plexus / Q000737:chemistry / Q000648:ultrastructure; D019879:Paneth Cells / Q000737:chemistry / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*
chemical_list: D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin