Seven transmembrane domain receptor subtypes identified in NG108-15 cells by reverse transcription-polymerase chain reaction.

NG108-15 neuroblastoma x glioma cells are widely used for the study of neurotransmitter receptors. We utilized reverse transcription-polymerase chain reaction to amplify members of the seven transmembrane domain class of G-protein linked receptors using RNA isolated from NG108-15 cells. Two complementary DNAs representing receptors were obtained; based upon comparison with the sequence database, they probably represent the murine dopamine D1A receptor and a receptor closely related to the serotonin 5HT1D receptor subtype. The finding of the 5HT receptor subtype is of interest, as only the 5HT3 subtype was previously identified in NG108-15 cells by pharmacological means. Certain responses of NG108-15 cells to serotonin have been described that do not appear to be mediated by known 5HT receptor subtypes. The cDNA we cloned may therefore represent an additional 5HT1D subclass.

Allele frequencies of the preproenkephalin A (PENK) gene CA repeat in Asians, African-Americans, and Caucasians: lack of evidence for different allele frequencies in alcoholics.

Evidence from animal models and from recent reports on the efficacy of the opioid antagonist naltrexone in the treatment of alcoholism suggests that the endogenous opioid systems may play a role in alcohol seeking behavior. The gene encoding preproenkephalin A (PENK) is flanked at its 3' end by a polymorphic (CA)n repeat. We determined the allele frequencies for this locus in samples of Chinese and Atayal living in Taiwan, Caucasians living in the United States and Byelorussia, and African-Americans living in the United States. We compared the allele frequencies of nonalcoholics in each population with those of alcoholics with or without alcohol-induced organ pathology. There was no difference in allele frequencies within any racial group when alcoholics with or without organ pathology were compared; there was also no difference in allele frequency between nonalcoholics and alcoholics within the two Asian populations, Caucasians, or African-Americans. There were highly significant differences in the frequency of the various length polymorphisms between the Asian, Caucasian, and African-American samples.