RESUMO
BACKGROUND: Activation of the dopaminergic (DA) neurons of the ventral tegmental area (VTA) by ethanol has been implicated in its rewarding and reinforcing effects. At most central synapses, ethanol generally increases inhibitory synaptic transmission; however, no studies have explored the effect of acute ethanol on GABAergic transmission in the VTA. METHODS: Whole-cell patch clamp recordings of inhibitory postsynaptic currents (IPSCs) from VTA-DA neurons in midbrain slices from young rats. RESULTS: Acute exposure of VTA-DA neurons to ethanol (25 to 50 mM) robustly enhanced GABAergic spontaneous and miniature IPSC frequency while inducing a slight enhancement of spontaneous IPSC (sIPSC) amplitude. Ethanol (50 mM) enhanced paired-pulse depression of evoked IPSCs, further suggesting enhanced GABA release onto VTA-DA neurons. The frequency of sIPSCs was suppressed by the GABA(B) agonist, baclofen (1.25 microM) and enhanced by the antagonist, SCH50911 (20 microM); however, neither appeared to modulate or occlude the effects of ethanol on sIPSC frequency. CONCLUSIONS: The present results indicate that ethanol increases postsynaptic GABA(A) receptor sensitivity, enhances action potential-independent GABA release onto VTA-DA neurons, and that this latter effect is independent of GABA(B) auto-receptor inhibition of GABA release.
Assuntos
Dopamina/fisiologia , Etanol/farmacologia , Neurônios/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , Área Tegmentar Ventral/citologia , Ácido gama-Aminobutírico/metabolismo , Animais , Feminino , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Masculino , Neurônios/fisiologia , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/fisiologia , Receptores de GABA-B/fisiologiaRESUMO
Analysis of the marine black prickleback Xiphister atropurpureus Kittlitz using 76 bp paired-end Illumina sequences resulted in the assembly of its complete mitogenome. The mitogenome is 16,518 bp in length and contains an origin of light strand replication (OL), control region, 22 tRNA, 2 rRNA, and 13 protein-coding genes. Content and organization of the X. atropurpureus mitogenome is consistent with other teleost. Phylogenetic analysis of X. atropurpureus resolves it in a clade with another member of the Stichaeidae, Chirolophis japonicus Herzenstein.