Silkis I. The cortico-basal ganglia-thalamocortical circuit with synaptic plasticity. I. Modification rules for excitatory and inhibitory synapses in the striatum.
Biosystems 2000;
57:187-96. [PMID:
11084240 DOI:
10.1016/s0303-2647(00)00134-9]
[Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It is pointed out that Ca(2+)-dependent modification rules for NMDA-dependent (NMDA-independent) synaptic plasticity in the striatum are similar to those in the neocortex and hippocampus (cerebellum). A unitary postsynaptic mechanism of synaptic modification is proposed. It is based on the assumption that, in diverse central nervous system structures, long-term potentiation/depression (LTP/LTD) of excitatory transmission (depression/potentiation of inhibitory transmission, LTDi/LTPi) is the result of an increasing/decreasing the number of phosphorylated AMPA and NMDA (GABA(A)) receptors. According to the suggested mechanism, Ca(2+)/calmodulin-dependent protein kinase II and protein kinase C, whose activity is positively correlated with Ca(2+) enlargement, together with cAMP-dependent protein kinase A (cGMP-dependent protein kinase G, whose activity is negatively correlated with Ca(2+) rise) mainly phosphorylate ionotropic striatal receptors, if NMDA channels are opened (closed). Therefore, the positive/negative post-tetanic Ca(2+) shift in relation to a previous Ca(2+) rise must cause NMDA-dependent LTP+LTDi/LTD+LTPi or NMDA-independent LTD+LTPi/LTP+LTDi. Dopamine D(1)/D(2) or adenosine A(2A)/A(1) receptor activation must facilitate LTP+LTDi/LTD+LTPi due to an augmenting/lowering PKA activity. Activation of muscarinic M(1)/M(4) receptors must enhance LTP+LTDi/LTD+LTPi as a consequence of an increase/decrease in the activity of protein kinase C/A. The proposed mechanism is in agreement with known experimental data.
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