Rapid Temporal Changes in the Expression of a Set of Neuromodulatory Genes During Alcohol Withdrawal in the Dorsal Vagal Complex: Molecular Evidence of Homeostatic Disturbance
ALCOHOLISM-CLINICAL AND EXPERIMENTAL RESEARCH
Authors: Freeman, Kate; Staehle, Mary M.; Guemues, Zeynep H.; Vadigepalli, Rajanikanth; Gonye, Gregory E.; Nichols, Carmen N.; Ogunnaike, Babatunde A.; Hoek, Jan B.; Schwaber, James S.
Abstract
Background Chronic alcohol exposure produces neuroadaptation, which increases the risk of cellular excitotoxicity and autonomic dysfunction during withdrawal. The temporal progression and regulation of the gene expression that contributes to this physiologic and behavioral phenotype is poorly understood early in the withdrawal period. Further, it is unexplored in the dorsal vagal complex (DVC), a brainstem autonomic regulatory structure. Methods We use a quantitative polymerase chain reaction platform to precisely and simultaneously measure the expression of 145 neuromodulatory genes in more than 100 rat DVC samples from control, chronically alcohol-exposed, and withdrawn rats. To gain insight into the dynamic progression and regulation of withdrawal, we focus on the expression of a subset of functionally relevant genes during the first 48 hours, when behavioral symptoms are most severe. Results In the DVC, expression of this gene subset is essentially normal in chronically alcohol-exposed rats. However, withdrawal results in rapid, large-magnitude expression changes in this group. We observed differential regulation in 86 of the 145 genes measured (59%), some as early as 4 hours into withdrawal. Time series measurements (4, 8, 18, 32, and 48 hours after alcohol removal) revealed dynamic expression responses in immediate early genes, ?-aminobutyric acid type A, ionotropic glutamate, and G-protein coupled receptors and the Ras/Raf signaling pathway. Together, these changes elucidate a complex, temporally coordinated response that involves correlated expression of many functionally related groups. In particular, the expression patterns of Gabra1, Grin2a, Grin3a, and Grik3 were tightly correlated. These receptor subunits share overrepresented transcription factor binding sites for Pax-8 and other transcription factors, suggesting a common regulatory mechanism and a role for these transcription factors in the regulation of neurotransmission within the first 48 hours of alcohol withdrawal. Conclusions Expression in this gene set is essentially normal in the alcohol-adapted DVC, but withdrawal results in immediate, large-magnitude, and dynamic changes. These data support both increased research focus on the biological ramifications of alcohol withdrawal and enable novel insights into the dynamic withdrawal expression response in this understudied homeostatic control center.
Association between the ionotropic glutamate receptor kainate3 (GRIK3) Ser310Ala polymorphism and schizophrenia in the Indian population
WORLD JOURNAL OF BIOLOGICAL PSYCHIATRY
Authors: Ahmad, Yusra; Bhatia, Manjeet S.; Mediratta, Pramod K.; Sharma, Krishna K.; Negi, Harsh; Chosdol, Kunzang; Sinha, Subrata
Abstract
Various studies have been done to check the status of glutamate receptor gene in the pathogenesis of schizophrenia. The T928G (Ser310Ala) polymorphism of ionotropic glutamate receptor kainate 3 gene (GRIK3) and its positive association with schizophrenia was reported in Caucasians, whereas no association of this polymorphism with schizophrenia was shown in two other populations, Chinese and Japanese. However, no literature is available regarding the prevalence of this polymorphism and its association with schizophrenia in the Indian population. As genetic susceptibility profiles in India are often different from those of white Caucasians or Orientals, we investigated the status of Ser310Ala polymorphism of GRIK3 in 100 schizophrenic patients and 100 healthy controls in the Indian population by the PCR-RFLP (restriction fragment length polymorphism) method. A statistically significant difference in the genotype and allelic distributions (P < 0.000001 and P = 0.01, respectively) of Ser310Ala polymorphism was found in schizophrenics than in control, considering Ala-allele as being associated with the disease (OR = 1.7, 95% CI = 1.137 - 2.540). Our study suggests a potential role for GRIK3 for susceptibility to schizophrenia in Indian population.