Quantal transmission at mossy fibre targets in the CA3 region of the rat hippocampus

摘要: Recent anatomical evidence that inhibitory interneurones receive approximately 10 times more synapses from mossy fibres than do principal neurones (Acsady et al. 1998) has led to the re-examination of extent which are involved in CA3 network excitability. Although many and physiological properties fibre–CA3 interneurone have been previously described 1998; Toth 2000), an investigation into quantal nature transmission at this synapse not yet conducted. Here, we employed variance–mean (VM) analysis compare release probability, size (q) number sites (n) fibre target CA3. At six seven a high concentration Ca2+ was experimentally imposed, relationship could be approximated by parabola. Estimates n were 1–2, weighted probability normal conditions ranged 0.34 0.51. pyramidal cell synapses, linear relationship, suggesting significantly lower. The amplitude similar although variability larger synapses. Mossy can explained lower sites, broader range probabilities, amplitudes Finally, events on elicited spike transmission, owing part depolarized membrane potential cells. These results suggest cells associated with per synapse, higher connectivity, initial relative impact quantum generate strong feedforward inhibition firing frequencies dentate granule Given central role synaptic these details should provide insight dynamics under both pathophysiological circumstances.