In brain, [M.sub.1] receptors are most commonly located postsynaptically while [M.sub.2] receptors are most commonly located
presynaptically (3) (Figure 1).
schneideri poison was shown to act
presynaptically by irreversibly blocking acetylcholine release; no co-participation of post-synaptic nicotinic receptors on the neuromuscular blockade was observed (Rostelato-Ferreira, Dal Belo, Cruz-Hofling, Hyslop, & Rodrigues-Simioni, 2011).
[10-13] The [Ca.sub.v] 2.1 encodes for both P and Q type calcium channels and these channels are highly expressed
presynaptically where they are critically involved in neurotransmission and synaptic efficacy and therefore have a great influence on neuronal excitability.
Conversely, another study has suggested that oxytocin depresses spontaneously occurring GABA receptor-mediated inhibitory potential by acting
presynaptically in the olfactory blub [53].
The toxin affects nerves
presynaptically by inhibiting the release of acetylcholine at cholinergic nerve endings (17).
Nociceptin/orphanin FQ
presynaptically decreases GABAergic transmission and blocks the ethanol-induced increase of GABA release in central amygdala.
Tsumoto, "
Presynaptically silent synapses: spontaneously active terminals without stimulus-evoked release demonstrated in cortical autapses.", J.
GABA released from basket cells not only produces IPSCs on PCs through GABAa receptors but also accesses neighboring excitatory glutamate synapses by diffusion, thereby
presynaptically inhibiting the release of glutamate by [GABA.sub.B] receptors [33].
[CB.sub.1] receptors also exhibit particularly high density on the presynaptic terminals of GABA and glutamate neurons, (30) with [CB.sub.1] inhibiting GABA transmission
presynaptically. (31) New research in rat models posits that [CB.sub.1] activation may potentially induce dopamine release in the striatum including the nucleus accumbens, which has important implications for the reward pathway.
To determine whether non-NMDA receptors regulate sIPSCs or mIPSCs
presynaptically or postsynaptically, we examined the effects of DNQX on mIPSCs.