Premium
Depolarization‐induced suppression of inhibition mediated by endocannabinoids at synapses from fast‐spiking interneurons to medium spiny neurons in the striatum
Author(s) -
Narushima Madoka,
Uchigashima Motokazu,
Hashimoto Kouichi,
Watanabe Masahiko,
Kano Masanobu
Publication year - 2006
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2006.05119.x
Subject(s) - medium spiny neuron , endocannabinoid system , inhibitory postsynaptic potential , neuroscience , excitatory postsynaptic potential , gabaergic , interneuron , neurotransmission , cannabinoid receptor , depolarization induced suppression of inhibition , striatum , postsynaptic potential , direct pathway of movement , biology , chemistry , parvalbumin , dopamine , receptor , biochemistry , agonist
Endogenous cannabinoids (endocannabinoids) act as retrograde inhibitory messengers in various regions of the brain. We have recently reported that endocannabinoids mediate short‐term retrograde suppression of excitatory synaptic transmission from the neocortex to medium spiny (MS) neurons, the major projection neurons from the striatum. However, it remains unclear whether endocannabinoids modulate inhibitory transmission in the striatum. Here we show that depolarization of MS neurons induces transient suppression of inhibition that is mediated by retrograde endocannabinoid signalling. By paired recording from a fast‐spiking (FS) interneuron and an MS neuron, we demonstrated that FS–MS inhibitory synapses undergo endocannabinoid‐mediated retrograde suppression. We verified that GABAergic inhibitory terminals immunopositive for parvalbumin (PV), a marker for FS interneurons, expressed CB1 receptors. These PV–CB1 double‐positive terminals surrounded dopamine D1 receptor‐positive and D2 receptor‐positive MS neurons; these constitute direct and indirect pathways, respectively. These results suggest that endocannabinoid‐mediated retrograde suppression of inhibition influences information flow along both direct and indirect pathways, depending on the activity of MS neurons.