The mesolimbic system is known to play a role in self-administration of opioids and psychostimulants. Although morphine and cocaine act by separate cellular mechanisms initially, the present study describes a common change in synaptic regulation of dopamine cells in the ventral tegmental area 1 week after termination of chronic treatment with either drug. Normally, D1 receptor activation augmen...

GABA(C) receptors are the least studied of the three major classes of GABA receptors. The physiological roles of GABA(C) receptors are still being unravelled and the pharmacology of these receptors is being developed. A range of agents has been described that act on GABA(C) receptors with varying degrees of specificity as agonists, partial agonists, antagonists and allosteric modulators. Pharma...

The uptake of 36Cl- into the fraction of membrane vesicles from rat and rabbit cortex and rabbit hippocampus was measured to investigate the selectivity of agonists and antagonists of inhibitory amino acid receptors coupled to chloride channels in the forebrain gamma-Aminobutyric acid (GABA) produced a dose-dependent 36Cl- uptake into membrane vesicles, whereas glycine and taurine were ineffect...

Receptive-field plasticity within the auditory neocortex is associated with learning, memory, and acetylcholine (ACh). However, the interplay of elements involved in changing receptive-fields remains unclear. Herein, we describe a depolarizing and a hyperpolarizing potential elicited by repetitive stimulation (20-100 Hz, 0.5-2 sec) and dependent on ACh, which may be involved in modifying recept...

NMDA receptors mediate excitatory postsynaptic potentials throughout the brain but, paradoxically, NMDA receptor antagonists produce cortical excitation in humans and behaving rodents. To elucidate a mechanism for these diverging effects, we examined the effect of use-dependent inhibition of NMDA receptors on the spontaneous activity of putative GABA interneurons and pyramidal neurons in the pr...

In the adult cerebral cortex, the neurotransmitter GABA is strongly inhibitory, as it profoundly decreases neuronal excitability and suppresses the network propensity for synchronous activity. When fast, GABA(A) receptor (GABA(A)R)-mediated neurotransmission is blocked in the mature cortex, neuronal firing is synchronized via recurrent excitatory (glutamatergic) synaptic connections, generating...

The GABA(B) receptor agonist baclofen enhances the epileptiform activity induced by 4-aminopyridine (4AP) in juvenile rat hippocampal slices. In this study, we used a similar experimental approach (i.e., field potential, intracellular, and [K+]o recordings in the CA3 area of slices obtained from 15-23-day-old rats) to establish whether antagonizing GABA(B) receptors could exert opposite (presum...

GABA(A) and GABA(B) receptors are present in the lateral parabrachial nucleus (LPBN), a pontine area involved with inhibitory mechanisms related to the control of sodium appetite. Activation of GABA(A) receptors in the LPBN induces strong ingestion of 0.3 M sodium chloride (NaCl) in normonatremic and euhydrated rats. In the present study, we investigated the effects of the GABA(B) receptor agon...

spreading depression (sd), discovered by leao in 1944, is a pathophysiological wave which propagates slowly in the brain (3 mm/min) and cause dramatic ionic and hemodynamic changes. sd appears to act through several mechanisms and receptors which have not completely understood. here, we studied the effect of inhibitory system in animal model of sd using immunohistochemistry technique. after imp...

A) Representative recording samples showing the membrane potential recorded from POMC neurons following treatment with leptin (leptin; 100nM) at 2.5 mM glucose in the absence (left) or presence (right) of the GABA A receptor antagonist picrotoxin (100 M) without glutamatergic influences. Leptin reduced POMC neuronal activity in the absence of the GABA A receptor antagonist, whereas POMC neuron...