piperidines has been researched along with picrotoxinin* in 1 studies
1 other study(ies) available for piperidines and picrotoxinin
| Article | Year |
|---|---|
Control of serotonergic function in medial prefrontal cortex by serotonin-2A receptors through a glutamate-dependent mechanism.
We examined the in vivo effects of the hallucinogen 4-iodo-2,5-dimethoxyamphetamine (DOI). DOI suppressed the firing rate of 7 of 12 dorsal raphe (DR) serotonergic (5-HT) neurons and partially inhibited the rest (ED(50) = 20 microg/kg, i.v.), an effect reversed by M100907 (5-HT(2A) antagonist) and picrotoxinin (GABA(A) antagonist). DOI (1 mg/kg, s.c.) reduced the 5-HT release in medial prefrontal cortex (mPFC) to 33 +/- 8% of baseline, an effect also antagonized by M100907. However, the local application of DOI in the mPFC increased 5-HT release (164 +/- 6% at 100 microm), an effect antagonized by tetrodotoxin, M100907, and BAY x 3702 (5-HT(1A) agonist) but not by SB 242084 (5-HT(2C) antagonist). The 5-HT increase was also reversed by NBQX (AMPA-KA antagonist) and 1S,3S-ACPD (mGluR 2/3 agonist) but not by MK-801 (NMDA antagonist). AMPA mimicked the 5-HT elevation produced by DOI. Likewise, the electrical-chemical stimulation of thalamocortical afferents and the local inhibition of glutamate uptake increased the 5-HT release through AMPA receptors. DOI application in mPFC increased the firing rate of a subgroup of 5-HT neurons (5 of 10), indicating an enhanced output of pyramidal neurons. Dual-label fluorescence confocal microscopic studies demonstrated colocalization of 5-HT(1A) and 5-HT(2A) receptors on individual cortical pyramidal neurons. Thus, DOI reduces the activity of ascending 5-HT neurons through a DR-based action and enhances serotonergic and glutamatergic transmission in mPFC through 5-HT(2A) and AMPA receptors. Because pyramidal neurons coexpress 5-HT(1A) and 5-HT(2A) receptors, DOI disrupts the balance between excitatory and inhibitory inputs and leads to an increased activity that may mediate its hallucinogenic action. Topics: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Amphetamines; Animals; Dose-Response Relationship, Drug; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; Female; Fluorobenzenes; GABA Antagonists; Glutamic Acid; Hallucinogens; Male; Mice; Mice, Inbred BALB C; Microdialysis; Neurons; Picrotoxin; Piperidines; Prefrontal Cortex; Raphe Nuclei; Rats; Rats, Wistar; Receptor, Serotonin, 5-HT2A; Receptors, Serotonin; Receptors, Serotonin, 5-HT1; Serotonin; Serotonin Antagonists; Serotonin Receptor Agonists; Sesterterpenes; Tetrodotoxin | 2001 |