title: Nerve extract induces increase and redistribution of acetylcholine receptors on cloned muscle cells.
abstract: The effect of rat spinal cord explants and cell-free nerve extract on acetylcholine receptor site density and distribution was studied using (125)I- and rhodamine-labeled alpha-bungarotoxin on L(6), a cloned rat muscle cell line. Control L(6) myotubes have a low and uniform distribution of acetylcholine receptors (20 +/- 3 sites per mum(2) in the present study). The addition of spinal cord explants caused an increase in average receptor site density of about 6 times on myotubes within 2 mm of the explant, while a smaller increase of 3 times was observed at distances greater than 5 mm. The formation of high-density patches of receptors was also stimulated. These observations suggested that a diffusible substance originating from the explant was responsible for these changes. Cell-free homogenates of the central nervous system were prepared and found to produce the same effects. The effect of the homogenate was not strongly dependent on the age of the fetus from which the tissue was isolated, and fetal liver had little or no effect. The active component(s) appears to be a protein(s) with a molecular weight of about 100,000. Because the nerve homogenates make the L(6) cells resemble primary muscle cultures, we suggest that a common factor is responsible for regulating the acetylcholine receptor in the two types of muscle culture. The normally acetylcholine receptor-poor L(6) cells may provide a more sensitive assay for these factors than do primary muscle cultures.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000166:cytology; D002038:Bungarotoxins / Q000378:metabolism; D002460:Cell Line; D009132:Muscles / Q000378:metabolism*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D002038:Bungarotoxins; D011950:Receptors, Cholinergic; D014020:Tissue Extracts; D000109:Acetylcholine
references.citation: J Biol Chem. 1951 Nov;193(1):265-75
references.pmid: 14907713
references.citation: J Physiol. 1977 Jul;268(3):757-73
references.pmid: 69707
references.citation: J Physiol. 1977 Jul;268(3):731-56
references.pmid: 69706
references.citation: Dev Biol. 1977 Aug;59(1):24-38
references.pmid: 892219
references.citation: Anal Biochem. 1977 Jun;80(2):585-92
references.pmid: 889094
references.citation: Proc Natl Acad Sci U S A. 1976 Dec;73(12):4594-8
references.pmid: 1070010
references.citation: J Physiol. 1975 May;247(2):343-61
references.pmid: 168354
references.citation: J Exp Zool. 1976 May;196(2):131-50
references.pmid: 5574
references.citation: Proc Natl Acad Sci U S A. 1973 Jan;70(1):270-4
references.pmid: 4509661
references.citation: Proc Natl Acad Sci U S A. 1972 Oct;69(10):2762-6
references.pmid: 4507600
references.citation: Physiol Rev. 1975 Jan;55(1):1-61
references.pmid: 162810
references.citation: Nature. 1974 Dec 13;252(5484):593-4
references.pmid: 4431523
references.citation: Exp Neurol. 1974 Dec;45(3):520-6
references.pmid: 4435074
references.citation: Dev Biol. 1973 Mar;31(1):147-62
references.pmid: 4787184
references.citation: J Gen Physiol. 1973 Sep;62(3):255-70
references.pmid: 4738329
references.citation: Science. 1972 Dec 22;178(4067):1298-300
references.pmid: 4640069
references.citation: J Cell Biol. 1976 Apr;69(1):144-58
references.pmid: 1254640
references.citation: Exp Neurol. 1976 Feb;50(2):376-86
references.pmid: 1248557
references.citation: Exp Neurol. 1975 Feb;46(2):432-8
references.pmid: 1116511
references.citation: Proc Natl Acad Sci U S A. 1968 Oct;61(2):477-83
references.pmid: 5245982