[Pretective action of peptide pro-gly-pro on electrophysiological characteristics of cultured hippocampal neurones during excitotoxic damage].

Electrophysiological characteristics of hippocampal neurones cultured with Pro-Gly-Pro peptide were studied using glutamate excitotoxisity model (excitotoxic damage was induced by 100 mkM glutamate application during 5 min). It was found that negative changes in neurones cultured with 10 mcM Pro-Gly-Pro were less prominent if compared with control ones. Culturing with the peptide significantly affected the following parameters: resting potential (-55 +/- 4 mV in control; -29 +/- 6 MV after glutamate application; -38 +/- 5 MV cultured after glutamate application), action potential amplitude (91 +/- 4; 65 +/- 5; 84 +/- 5 mV), duration (4,3 +/- 0,4; 9,5 +/- 1,6; 5,2 +/- 0,7 ms), depolarization (56 [38, 84]; 27 [21, 35]; 46 [28, 62] MV/Ms) and repolarization (-29 [-38, -27]; -20 [-21, -18]; -29 [-33, -22] M(V)/MS) rates.

[Characteristics of quantal release of glutamate and GABA in synapses between retinal ganglion cells and superior colliculus neurons in coculture].

We investigated features of quantal release of glutamate and GABA in synapses between retinal ganglion cells (RGC) and superior colliculus (SC) neurons in coculture using dual patch-clamp technique. The main quantal characteristics of neurotransmitters release were defined on the basic of quantal analysis. Number of released quanta distributions for both neurotransmitters were corresponded to the binomial law.

[Changes in the kinetics of calcium signals in response to high frequency stimulation in the cultured hippocampal neurons].

Dynamic changes in the intracellular free Ca2+ concentration ([Ca2+]i) were studied in hippocampal cultured neurons using fluorescent Ca(2+)-indicator dye Indo-1 and somatic whole-cell recordings. During the tetanus stimulation Ca(2+)-transient increased their amplitude up to a steady-state level during repetitive stimulation. We identified two groups of neurons based on Ca-signal dynamics after the end of stimulation: the first group (n = 24) with the monoexponential decay of [Ca2+]i direct after the end of the tetanus; the second group (n = 32) with the monoexponential delayed [Ca2+]i decay after the end of the tetanus, the duration of delay varied from 1 to 27 s and depended on duration and frequency of stimulation.

[Electrical properties of retinal ganglion cells of rats with streptozotocine-induced diabetes].

On isolated retinal preparation from STZ-induced diabetic rats in whole-cell configuration the basic electrical properties of retinal ganglion cells (RGC) were studied. It was shown that on 8th week after STZ maximal depolarization-induced firing frequency is reduced and decay time constant of high-frequency stimulation-induced calcium signals is increased as compared to controls. The data obtained suggest functional changes in RGC of STZ-induced diabetic rats, possible mechanisms of such changes are discussed.

[Pre- and postsynaptic expression mechanisms of long-term depression in rats glutamatergic primary afferent synapses on dorsal horn spinal cord neurons in co-culture].

In co-culture of dorsal root ganglion (DRG) and dorsal horn (DH) neurons we studied the long-term depression (LTD) caused by 5 sec(-1) low-frequency stimulation (LFS) of DRG neurons. Dual whole-cell patch clamp recording in the pairs of DRG and DH neurons was used. The monosynaptic AMPA-receptor mediated eEPSC initiated in DH neurons by LFS of DRG neurons were analyzed.