Whole-cell patch-clamp recordings of GABAergic IPSCs were made from cholinergic interneurones in slices of striatum from developing rats aged 21-60 days postnatal. In addition, the Ca²⁺ channel subtypes involved in synaptic transmission, as well as dopamine (DA)-induced presynaptic inhibition, were investigated pharmacologically with development by bath application of Ca²⁺ channel blockers and DA receptor agonists. The IPSC amplitude was reduced by -conotoxin GVIA (-CgTX) or -agatoxin TK (-Aga-TK) across the whole age range, suggesting that multiple types of Ca²⁺ channels mediate transmission of the synapse. The IPSC fraction reduced by -CgTX significantly decreased, whereas that reduced by -Aga-TK remained unchanged with development. DA or quinpirole, a D₂-like receptor agonist, presynaptically reduced the IPSC amplitude throughout development. The DA-induced inhibition decreased with age in parallel with the decrease in N-type Ca²⁺ channels. DA showed no further inhibition of IPSCs after the inhibitory effect of -CgTX had reached steady state throughout development. These results demonstrate that there is a functional link between presynaptic N-type Ca²⁺ channels and D₂-like DA receptors at inhibitory synapses in the striatum. They also demonstrate that the suppression of GABAergic transmission by D₂-like receptors is mediated by modulation of N-type Ca²⁺ channels and decreases in parallel with the developmental decline in the contribution of N-type Ca²⁺ channels to exocytosis.