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Optimization and pharmacological characterization of receptor‐mediated G i/o activation in postmortem human prefrontal cortex
Author(s) -
Odagaki Yuji,
Kinoshita Masakazu,
Ota Toshio,
Meana J. Javier,
Callado Luis F.,
GarcíaSevilla Jesús A.
Publication year - 2019
Publication title -
basic and clinical pharmacology and toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.805
H-Index - 90
eISSN - 1742-7843
pISSN - 1742-7835
DOI - 10.1111/bcpt.13183
Subject(s) - prefrontal cortex , neuroscience , human brain , receptor , characterization (materials science) , chemistry , biology , biochemistry , materials science , nanotechnology , cognition
The biochemical abnormalities in transmembrane signal transduction mediated through G protein‐coupled receptors (GPCRs) have been postulated as underlying pathophysiology of psychiatric diseases such as schizophrenia and mood disorders. In the present study, the experimental conditions of agonist‐induced [ 35 S]GTPγS binding in postmortem human brain membranes were optimized, and the responses induced by a series of agonists were pharmacologically characterized. The [ 35 S]GTPγS binding assay was performed in postmortem human prefrontal cortical membranes by means of filtration techniques, and standardized as to GDP concentration, membrane protein content, MgCl 2 and NaCl concentrations in assay buffer, incubation period and effect of white matter contamination. Under the standard assay conditions, the specific [ 35 S]GTPγS binding was stimulated by the addition of 15 compounds in a concentration‐dependent manner. Of these agonists, R (+)‐8‐OH‐DPAT, UK‐14,304, DAMGO and DPDPE showed apparently biphasic concentration‐response curves. As for these four responses, only higher‐potency site was pharmacologically characterized. The receptors involved in the responses investigated were 5‐HT 1A receptor (probed with R (+)‐8‐OH‐DPAT or 5‐HT), α 2A ‐adrenoceptor (UK‐14,304 or (−)‐epinephrine), M 2 /M 4 mAChRs (carbachol), adenosine A 1 receptor (adenosine), histamine H 3 receptor (histamine), group II mGlu ( l ‐glutamate), GABA B receptor (baclofen), μ‐opioid receptor (DAMGO or endomophin‐1), δ‐opioid receptor (DPDPE or SNC‐80) and NOP (nociceptin). Although dopamine also activated specific [ 35 S]GTPγS binding, this response was likely mediated via α 2A ‐adrenoceptor, but not dopamine receptor subtypes. The present study provides us with fundamental aspects of the strategy for elucidation of probable abnormalities of neural signalling mediated by G proteins activated through multiple GPCRs in the brain of psychiatric patients.