Fast synaptic transmission in the goldfish CNS mediated by multiple nicotinic receptors

摘要: Non-technicalsummaryUsually nicotinic receptors in the central nervous system only influence strength of a signal between neurons. At few critical connections, for instance some those involved flight response, not modulate signal, they actually determine whether is conveyed or not. We show at one such connections accessible study, up to three different receptor subtypes mediate signal. The subtypesappeartobeclusteredinseparatelocations.Dependingonthenumberandcombination present can range from short long duration and low high amplitude.Thisprovidesacriticalconnectionwithabuilt-inplasticityandmayenableittoadapt changing environment. Abstract In this fast synaptic transmission vertebrate CNS mediated by several ACh (nAChRs) was investigated with paired recordings pre- postsynaptic Analysis response kinetics axo-axonic Mauthner (M-) axon cranial relay neurons (CRN) indicates main componentsarepresentandcanbecharacterizedbyfast, ∼1.5ms,intermediate, ∼6msandslow, ∼15ms, decay time constants. Further analysis most responses have multiexponential decays each falls into six classes dependent on weight combination kinetic components. Pharmacological results suggest that nAChRs, α7 ∗ , α3β2 α3β4 ,mediatethepostsynapticresponsesandcorrespondtothefast,intermediateandslowdecay components, respectively. component blocked ∼35nM methyllycaconitine (MLA), 100 nM α-bungarotoxin (α-Btx) 150 α-conotoxin (α-Ctx) ArIB. intermediate 2 μM dihydro-beta-erythroidine (DHβE) 200 α-Ctx GIC. slow 10 AuIB, but 7.25 DHβE. Intriguingly, mEPSPs (minis) evoked EPSPs best fitted multiple exponentials, were composite; rather, there populations minis, single exponential times corresponding EPSP Thisindicatesthatthedifferentreceptorsaretopographicallysegregatedattheconnectionbetween M-axon CRN axon. These that, as glutamate, be same neuron. coexistence durations may implications network function plasticity.