Influence of chronic alcohol consumption on histaminergic neurons of the rat brain

Fundamental features of receptor-mediated Gαi/o activation in human prefrontal cortical membranes: A postmortem study

To elucidate possible abnormalities in transmembrane signal transduction in psychiatric diseases, use of autopsy brain is a feasible approach. However, postmortem studies should be interpreted with caution concerning such factors as age, gender, psychotropic drug history, agonal state, postmortem delay (PMD), and storage period. In this study, agonist-induced [³⁵S]GTPγS binding was performed in postmortem dorsolateral prefrontal cortical membranes of 40 control subjects. In addition to the previously reported G protein-coupled receptor (GPCR)-mediated G_i/o activation, κ-opioid receptor-mediated [³⁵S]GTPγS binding was detected by using U-50,448. The responses elicited by 16 different agonists were determined, and the effects of several factors were investigated. Gender difference was negligible. Concentration-response curve of histamine H₃ receptor-mediated [³⁵S]GTPγS binding was shifted rightward in the subjects with some drugs detected at toxicological screening. Age-related alterations were minimal, except for the age-dependent supersensitivity of μ-opioid receptor-mediated Gα_i/o activation, revealed by endomorphin-1- and DAMGO-stimulated [³⁵S]GTPγS binding. Age-related increase in %E_max values was also detected as to DPDPE-induced [³⁵S]GTPγS binding through δ-opioid receptors. With an exception of NOP receptor/G-protein coupling, GPCR-mediated [³⁵S]GTPγS binding is relatively stable irrespective of PMD or storage period. There were many positive correlations among the %E_max values for different receptor subtypes, which might reflect formation of heterodimer complex of such GPCRs coupled to the same G_i/o proteins. These results provide us with important fundamental data in the future project using human postmortem brains from patients with psychiatric disorders.

Effects of Alcohol on Mitochondrial Functions of Cumulus Cells in Mice

Alcohol is an important compound used in food, agriculture, and medicine. In this study, we investigated the effect of alcohol on oocyte quality in mice by exposing animals for different duration times during an estrous cycle. Cumulus-oocyte complexes were collected from mice after pregnant mare serum gonadotropin- and human chorionic gonadotropin-induced superovulation. Ovulation number, E₂ level in serum, and parthenogenetic embryo development in vitro were evaluated. Mitochondrial gene expression, mitochondrial membrane potential, and reactive oxygen species (ROS) levels in the cumulus were also assessed. The results showed that acute exposure to alcohol did not affect ovulation time (p > 0.05). Blasocyst formation rate in vitro was significantly improved after 1 and 2 days of alcohol exposure (p < 0.01). Mitochondrial membrane potential was significantly increased after 1-4 days of alcohol exposure (p < 0.05), but it decreased after 5 days (p < 0.05). ROS levels remained relatively low after 2, 3, and 4 days of exposure (p < 0.05), and they significantly increased after 6 days (p < 0.05). In addition, alcohol altered the expression of mitochondrial and nuclear genes in the cumulus. Taken together, our data suggest that acute exposure to alcohol affects oocyte quality by influencing the function and gene expression in the cumulus. These results underscore potential implications for the development of human reproductive therapeutics.