Session Title: Neurodevelopment and Neurodegeneration
DEVELOPMENTAL CHANGES IN THE CALCIUM CHANNEL AND D1-LIKE RECEPTORS INVOLVED IN THE GLUTAMATERGIC TRANSMISSION ONTO RAT BASAL FOREBRAIN CHOLINERGIC NEURONS
A whole-cell patch-clamp study was carried out using brain slice preparations of the rats (P21-38) to elucidate the developmental changes in calcium channel subtypes involved in non-NMDA glutamatergic transmission onto cholinergic neurons in the basal forebrain (BF) and D1-like receptor-mediated presynaptic inhibition. Pharmacologically-isolated non-NMDA EPSCs were evoked by focal stimulation. The EPSC fraction suppressed by ω-CgTX (3 µM), an N-type calcium channel blocker, decreased with age, whereas that suppressed by ω-Aga-TK (200 nM), a P/Q-type channel blocker, increased with age. Inhibition of EPSCs by SKF 81297, a D1-like receptor agonist, also increased with age in parallel with the increase in ω-Aga-TK-induced suppression. SKF 81297 showed no further inhibition of EPSCs after the effect of ω-Aga-TK had reached steady state throughout the developmental stages examined. These results suggest a tight functional linkage between presynaptic D1-like receptors and P/Q type channels for the glutamate release throughout development.