Stimulation of cloned human serotonin 5-HT1D beta receptor sites in stably transfected C6 glial cells promotes cell growth.
The involvement of serotonin 5-HT1D beta receptor sites was investigated in the growth of rat C6 glial cells permanently transfected with a gene encoding a human 5-HT1D beta receptor. The 5-HT receptor identity of control and transfected C6 glial/5-HT1D beta cells was determined by reverse transcription-polymerase chain reaction using primers specific for rat 5-HT1A, rat 5-HT1B, rat 5-HT1D alpha, human 5-HT1D beta, and rat 5-HT2A receptor genes. Constitutive mRNA for 5-HT2A receptors was present in control and transfected C6 glial/5-HT1D beta cells, whereas mRNA for 5-HT1D beta receptor sites was only present in the transfected C6 glial/5-HT1D beta cell line. 5-HT inhibited forskolin-stimulated cyclic AMP formation and promoted cell growth, in contrast to the absence of any measurable effect in pcDNA3 plasmid-transfected and nontransfected C6 glial cells. The 5-HT effects could be mimicked by sumatriptan (EC50 = 44-76 nM) and were totally and partially blocked by methiothepin (IC50 = 9 nM) and GR 127,935 (2'-methyl-4'-(5-methyl[1,2,4]oxadiazol-3-yl)-biphenyl-4-carbox yli c acid [4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]amide; IC50 = 97 pM), respectively. No effect on cell growth was measured with the 5-HT2 receptor agonist DOI [1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane; 10 microM], suggesting that 5-HT2A receptors are not involved in the 5-HT-stimulated C6 glial/5-HT1D beta cell growth. Dibutyryl-cyclic AMP (0.3 mM)-treated cultures did not show sumatriptan-promoted cell growth, indicating an inhibitory role for cyclic AMP in the cell growth mediated by 5-HT1D beta receptor sites.(ABSTRACT TRUNCATED AT 250 WORDS)
Pauwels
P J
PJ
Laboratory of Cellular and Molecular Neurobiology, Centre de Recherche Pierre Fabre, Castres, France.
Wurch
T
T
Amoureux
M C
MC
Palmier
C
C
Colpaert
F C
FC
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D001932:Brain Neoplasms / Q000473:pathology; D003994:Bucladesine / Q000494:pharmacology; D016466:CHO Cells; D002455:Cell Division; D003001:Cloning, Molecular; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000502:physiology; D005796:Genes; D005910:Glioma / Q000473:pathology; D006801:Humans; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D051381:Rats; D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012689:Sequence Homology, Nucleic Acid; D018490:Serotonin Agents / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin; D011994:Recombinant Proteins; D018490:Serotonin Agents; D005576:Colforsin; D003994:Bucladesine; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine