In this issue, Bruchas et al. (2011) uncover a novel stress-induced p38α MAPK signaling cascade within serotonergic neurons of the dorsal raphe nucleus that mediates depressive and drug-seeking behaviors. Their findings have potentially important implications for medication development.

Pattern formation in the brain Neurons in the developing brain cooperate to build circuits. Mountoufaris et al. found that ~50 variable protocadherin genes support a combinatorial identity code that allows millions of olfactory neuron axons to sort into ~2000 glomeruli. Sharing olfactory receptors drives axons to one glomerulus, and protocadherin diversity allows the multiple axons to touch eac...

Pilocarpine-induced status epilepticus (SE) produces many alterations in central nervous system neurotransmission. Previous work from our laboratory has demonstrated that intraperitoneal administration of pilocarpine 400 mg/kg significantly decreases not only muscarinic M1, M2 and Gabaergic receptors densities, but also decrease acetylcholinesterase (AChE) and increases superoxide dismutase and...

NMDA receptors, an ionotropic subtype of glutamate receptors (GluRs) forming high Ca(2+)-permeable cation channels, are composed by assembly of the GluRzeta subunit (NR1) with any one of four GluRepsilon subunits (GluRepsilon1-4; NR2A-D). In the present study, we investigated neuronal functions in mice lacking the GluRepsilon1 subunit. GluRepsilon1 mutant mice exhibited a malfunction of NMDA re...

Visual illusions and hallucinations are hallmarks of serotonergic hallucinogen-induced altered states of consciousness. Although the serotonergic hallucinogen psilocybin activates multiple serotonin (5-HT) receptors, recent evidence suggests that activation of 5-HT2A receptors may lead to the formation of visual hallucinations by increasing cortical excitability and altering visual-evoked corti...

Objective: Studies on the actions of exogenous agmatine in experimental models have shown its anti-convulsant effects. However, there are no findings regarding influence absence epilepsy. Therefore, we investigated effects occurrence spike-and-wave discharges (SWDs) Wistar Albino Glaxo Rijswijk rats (WAG/Rij) model genetic Material and Method: Three different doses (20, 40 or 80 mg/ kg) salin...

Serotonin (5-HT) acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs) in the mouse medial prefrontal cortex (mPFC), and found three distinct response types: long-lasting 5-HT(1A) (1A) receptor...

Serotonin is a widely investigated neurotransmitter in several psychopathologies, including suicidal behavior (SB); however, its role extends to several physiological functions involving the nervous system, as well as the gastrointestinal and cardiovascular systems. This review summarizes recent research into ten serotonergic genes related to SB. These genes - TPH1, TPH2, SLC6A4, SLC18A2, HTR1A...

Research in our laboratory, supported by NIDA and facilitated by Roger Brown, has indicated that serotonergic neuronal systems are involved in the discriminative stimulus effects of LSD. However, the only compounds that fully antagonize the LSD cue act at both serotonin (5-HT) and dopamine (DA) receptors. In addition, substitution for LSD in standard drug vs. no-drug (DND) discriminations does ...

Agents that modify serotonergic function have therapeutic potential for the treatment of visceral hypersensitivity, either through a direct effect on perception or through modulation of visceral tone or motility. Administration of selective serotonin reuptake inhibitors reduces oesophageal sensitivity to distension but not gastric sensitivity to distension. 5-HT ligands may also influence gastr...