Immunohistochemical localization of a GHB receptor-like protein isolated from rat brain
ABSTRACT Gamma-hydroxybutyrate (GHB) is a substance derived from the metabolism of GABA and is heterogeneously distributed in various regions of the brain. This compound possesses a neuromodulatory role on several types of synapses, particularly those using GABA as a neurotransmitter. At physiological concentrations, this effect of GHB is mediated via specific receptors that induce neuronal hyperpolarization and bind radioactive GHB with a specific distribution, ontogenesis, kinetics, and pharmacology. A membrane protein that possesses six to seven transmembrane domains and which binds and is activated by micromolar amounts of GHB was recently cloned from rat brain hippocampus. In order to study the regional and cellular distribution of this receptor in rat brain, we selected several specific peptides belonging to the extracellular domains of the receptor to be used as specific immunogens to raise polyclonal antibodies in the rabbit. Among the antisera obtained, one of them gave particularly good results in terms of specificity and reactivity at high dilution. Immunohistochemical analyses, both at the confocal and electron microscopic level, showed receptor protein distribution closely resembling the distribution of GHB high-affinity binding sites, except for cerebellum, where GHB receptor(s) of lower affinity exist(s). In all regions studied the GHB receptor-like protein labeling appears to be distributed specifically in neurons and not in glial cells. At the cellular level the antibody specifically labels dendrites, and no immunoreactivity was detected in presynaptic endings or in axons. Accordingly, electron microscopy reveals strong labeling of postsynaptic densities and of neuronal cytosol.
SourceAvailable from: Keita Ishiwari[Show abstract] [Hide abstract]
ABSTRACT: γ-hydroxybutyric acid (GHB) causes retrograde amnesia in juveniles and young adults. Earlier, we have reported that in adolescent rat, GHB impairs the hidden platform task performance in the Morris water maze. In the present study, a classical fear conditioning paradigm was used to examine the effects of GHB on the acquisition of contextual conditioning, a hippocampus-dependent associative task, and cued tone conditioning, a hippocampus-independent task, in adolescent rats. Administration of GHB before the presentation of tone-shock pairings dose-dependently disrupted the acquisition of contextual conditioning with no effect on tone conditioning, when conditioned fear was measured 24 h later. Administering GHB prior to testing did not disrupt either contextual or tone conditioning. These results demonstrate that in the adolescent rat exposure to GHB preferentially disrupt hippocampal-dependent learning.
[Show abstract] [Hide abstract]
ABSTRACT: The aim of this study was to analyze the connection between alcohol dependence and criminal behavior by an integrated genetic-environmental approach. The research, structured as a case-control study, examined 186 alcohol-dependent males; group 1 (N = 47 convicted subjects) was compared with group 2 (N = 139 no previous criminal records). Genetic results were innovative, highlighting differences in genotype distribution (p = 0.0067) in group 1 for single-nucleotide polymorphism rs 3780428, located in the intronic region of subunit 2 of the GABA B receptor gene (GABBR2). Some environmental factors (e.g., grade repetition) were associated with criminal behavior; others (e.g., attendance at Alcoholics Anonymous) were inversely related to convictions. The concomitant presence of the genetic and environmental factors found to be associated with the condition of alcohol-dependent inmate showed a 4-fold increase in the risk of antisocial behavior. The results need to be replicated on a larger population to develop new preventive and therapeutic proposals.Journal of Forensic Sciences 07/2013; 58(5). DOI:10.1111/1556-4029.12201 · 1.31 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: OUR CASE DESCRIBES CLINICAL FEATURES OF TWO FAMILIES DEFINED BY JOINT PHENOTYPES: sodium oxybate intolerance and elevated serum acylcarnitines. Oxybate intolerance variably presents as either cervical dystonia or sleep-related eating disorder. Our objective is to identify biological markers which predict a poor response to sodium oxybate as a treatment for disturbed sleep. Familial inheritance pattern, genotype analysis, multiorgan system involvement, and response to treatment suggest the presence of a secondary cause of fatty oxidation defect, i.e., mitochondrial disorder. Our case report supports the possible conclusion that variance in human mitochondrial metabolism may affect sodium oxybate tolerability. CITATION: Berner J. Sodium oxybate intolerance associated with familial serum acylcarnitine elevation. J Clin Sleep Med 2013;9(1):71-72.Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 01/2013; 9(1):71-2. DOI:10.5664/jcsm.2346 · 2.83 Impact Factor