Do Ca2+ channels share NMDA receptors in plasticity of synaptic transmission in the rat visual cortex?

We examined the involvement of Ca2+ channels in LTP of responses in rat vis ual cortex slices; Stimulating layer IV, field potentials including EPSP1 a nd EPSP2 from layer II/III were recorded. L-type Ca2+ channel blocker nifed ipine did not have a considerable effect on LTP of the responses. T-type Ca 2+ channel blocker Ni2+ decreased potentiation of EPSP1 and almost blocked that of EPSP2. Effect of visual experience on the function of the channels is also considered. These results indicate that T-type Ca2+ channels play a real role in stable LTP of EPSP2. Also the function of the channels was al most the same in dark and light reared visual cortices. NeuroReport 11:3887 -3891 (C) 2000 Lippincott Williams & Wilkins.