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Plasticity of identified synapses in Helix depends on presynaptic spike patternстатья
- Автор: Palikhova T.A.
- Журнал: J. Physiol. Paris
- Том: 96
- Год издания: 2002
- Первая страница: 154
- Последняя страница: 155
- Аннотация: Direct excitatory synaptic connections between identified neurons of the land snail Helix lucorum have been named identified synapses (Sokolov, Logunov, 1985; Palikhova, 2000). Postsynaptic cells for the identified synapses are the giant command neurons of the snail’s withdrawal behavior (Balaban, 1979). Presynaptic cells have been identified in the left parietal ganglion as primary sensory neurons. The studies of identified synapses revealed that these are plastic, cholinergic and morphologically complex consisting from several contacts. The presynaptic neurons respond to the mechanosensory stimulation of its local receptive fields at viscera by bursts of spikes. The bursts don’t change significally during repeated sensory stimulation. The command neurons respond to the same stimuli by compound excitatory postsynaptic potentials (cEPSPs) that decrease in amplitudes during repeated stimulation. Presynaptic spikes evoked by intracellular current injections into the presynaptic neuron result in elementary EPSPs (eEPSPs) in the command neurons. Amplitudes of eEPSPs elicited by single repeated presynaptic spikes also decrease in wide range of stimulation frequencies. Comparison of habituation curve for eEPSPs and cEPSPs revealed that elementary response decreased grater than complex one. This difference might be explained by homosynaptic potentiation dependent on bursts of spikes in the presynaptic neuron elicited by sensory stimulation. Thus habituation of compound EPSP reflects both depression and potentiation of elementary potentials (Sokolov, Palikhova, 1999).
- Добавил в систему: Палихова Татьяна Анатольевна