Neurons in hippocampal and striatal cell cultures respond to adenosine with an inhibitory potassium current. This response disappears during whole-cell patch-clamp recording which the is filled minimal saline. We have found that this loss of sensitivity can be prevented by including 100 microM GTP patch electrode filling solution. GDP less effective than supporting response, while GMP has little, if any, effect. Treatments known inhibit GTP-binding proteins (G-proteins) block...

We have examined the effect of adenosine on membrane properties cultured embryonic mouse striatal neurons using patch electrode techniques. Adenosine at 50 microM effectively blocked spontaneous action potential activity. or 2-chloroadenosine caused a slow hyperpolarization and, under voltage clamp, an outward current that was by 1 mM theophylline. ATP also slower and weaker than response could be The induced appears to carried potassium since (i) inward generated when cells were internally...

The roles of glutamate diffusion, uptake, and channel kinetics in shaping the AMPA receptor EPSC were examined at a calyceal synapse. decay was described by three exponential components: two matching desensitizing kinetics, third component least 10 times slower. slowest had identical voltage dependence to steady-state current selectively increased prolonged blockade indicating that slow represented rebinding partially desensitized receptors. data strong agreement with predictions model...

Although almost all ionotropic neurotransmitter receptors undergo desensitization, the onset and recovery of desensitization at a synapse have never been observed directly. We found changes in postsynaptic AMPA receptor sensitivity neurons chick cochlear nucleus, nucleus magnocellularis (nMAG), by photolysis caged glutamate immediately after activation single synaptic input. Additionally, was demonstrated via competition between synaptically released an exogenous nondesensitizing agonist,...

We have examined glutamate receptor desensitization in voltage-clamped embryonic chicken spinal cord neurons and postnatal rat hippocampal maintained culture. Rapid currents that rose 0.8-3.6 msec were evoked when was ionophoresed with 0.5- to 1.0-msec pulses. With prolonged pulses or brief, repetitive pulses, glutamate-evoked decayed rapidly a manner independent of holding potential. A similar occurred following close-range pressure ejection glutamate. The rapid, desensitizing current...

Neurons of the nucleus magnocellularis (nMAG) chick express AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate) receptors displaying unusually rapid kinetics desensitization (Raman and Trussell, 1992a). To investigate whether fast are present in other auditory neurons, we compared properties as well nonauditory cells. These included neurons nMAG, angularis, laminaris, cochlear ganglion, Purkinje cell layer cerebellum, ventral horn spinal cord, brainstem glossopharyngeal nerve...

Rathouz, Margaret and Laurence Trussell. Characterization of outward currents in neurons the avian nucleus magnocellularis. J. Neurophysiol. 80: 2824–2835, 1998. Neurons magnocellularis (NM) preserve timing auditory signals through convergence a variety voltage- ligand-gated ion channels. To understand better how these channels interact, we have characterized kinetics, voltage sensitivity, pharmacology NM brain slices. The reversal potential ( E rev ) varied with potassium concentration as...

1. The properties of evoked excitatory postsynaptic currents (EPSCs) and spontaneous miniature (mEPSCs) have been studied in neurons the nucleus magnocellularis (nMAG), one avian cochlear nuclei which receive somatic, calyceal innervation from auditory nerve fibres. Whole‐cell patch clamp techniques were used to voltage visually identified brain slices. 2. EPSCs resulting activation single axonal inputs on average ‐5.3 nA at a driving force ‐25 mV. Current‐voltage relationships for peak EPSC...

AMPA receptors mediate rapid glutamatergic synaptic transmission. In the mammalian cochlear nuclei, neurons receive excitatory input from either auditory nerve fibers, parallel or both fiber systems. The functional correlates of differences in source were examined by recording receptor-mediated, miniature EPSCs (mEPSCs) whole-cell voltage-clamp mode identified neurons. Bushy, octopus, and T-stellate cells ventral nucleus (VCN) tuberculoventral dorsal (DCN) most their nerve; fusiform inputs...

1. The permeability of AMPA (alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐ isoxazolepropionate) receptors in the chick cochlear nucleus, nucleus magnocellularis (nMAG), was examined by measuring shift reversal potential (Erev) current through glutamate or neurotransmitter‐gated channels solutions different ionic composition. 2. Outwardly rectifying glutamate‐activated currents outside‐out membrane patches showed rapid activation and desensitization. Erev glutamate‐evoked zero sodium dependent on...

The function of presynaptic terminals is regulated by intracellular Cl − , the levels which modify vesicular endocytosis and transmitter refilling mediate effects ligand-gated channels. Nevertheless, concentration in a central nerve terminal unknown, it unclear whether can regulate independently soma. Using perforated-patch recording mammalian synapse, we found that accumulate up to 21 m between four five times higher than their parent cell bodies. Changing [Cl ] did not alter glutamate...