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The defensive gill-withdrawal reflex in Aplysia has proven to be an attractive system for analyzing the neural mechanisms underlying simple forms of learning such as habituation, sensitization, and classic conditioning. Previous studies have shown that habituation is associated with synaptic depression and sensitization with presynaptic facilitation of(More)
1. To examine the dependence of gamma-aminobutyric acid (GABAA) receptor gating on the alpha-subunit isoform, we studied the kinetics of GABA-gated currents (IGABA) of receptors that differed in the alpha-subunit subtype, alpha 1 beta 2 gamma 2S and alpha 3 beta 2 gamma 2S. cDNAs encoding rat brain subunits were co-expressed heterologously in HEK-293 cells(More)
1. Individual Na+ channels from isolated guinea-pig ventricular heart cells were studied using the patch-clamp technique. To localize the selectivity region of the channels we investigated their blockade by a permanently charged quaternary ammonium ion (QX-314, 2-(triethylamino)-N-(2,6-dimethylphenyl)acetamide, 0-5 mM) that was applied to the cytoplasmic(More)
We have measured ionic and gating currents in human embryonic kidney (HEK 293) cells transiently transfected with cDNAs encoding subunits of the cardiac voltage-gated L-type Ca2+ channel. Robust recombinant ionic current and associated nonlinear charge movement could be measured over a broad voltage range without contamination by endogenous channel(More)
Steady-state, single-channel gating of GABA(A) receptors (GABARs ) is complex. Simpler gating may dominate when triggered by rapid GABA transients present during fast inhibitory synaptic transmission and is critical to understanding the time course of fast IPSCs. We studied the single-channel activity of expressed alpha1beta1gamma2 GABARs in outside-out(More)
Few studies have examined the influence of the age and the strain of mouse on the pharmacokinetics of psychostimulants, or the role of pharmacokinetics in age-related differences in drug responses. The present study compared concentrations of cocaine, and its metabolite, benzoylecgonine (BZE), in the blood and brain of early (P35) and later (P42)(More)
Presynaptic facilitation of transmitter release from sensory neurons is an important mechanism contributing to nonassociative and associative learning in Aplysia. In a previous modeling study (28,29), we concluded that enhancement of the postsynaptic potential (PSP) during presynaptic facilitation is mediated by at least two processes; spike broadening,(More)
Plasma ropivacaine levels produced by routine scalp infiltration for field block were assayed in eight patients undergoing awake intracranial surgery. Levels peaked within approximately 13 minutes, indicating rapid systemic absorption of ropivacaine. Potentially toxic plasma drug levels were achieved in three of eight patients, although no untoward effects(More)
3-tert-Butyl-7-(5-methylisoxazol-3-yl)-2-(1-methyl-1H-1,2,4triazol-5-ylmethoxy)-pyrazolo[1,5-d][1,2,4]triazine (MRK-016) is a pyrazolotriazine with an affinity of between 0.8 and 1.5 nM for the benzodiazepine binding site of native rat brain and recombinant human 1-, 2-, 3-, and 5-containing GABAA receptors. It has inverse agonist efficacy selective for the(More)
Recently, a novel cellular mechanism, activity-dependent neuromodulation, was identified in sensory neurons mediating the gill and tail withdrawal reflexes in Aplysia. This mechanism may explain associative learning on a behavioral level. The present study was designed to mathematically model subcellular events that may underlie this mechanism and to(More)