Regulation of [3H]norepinephrine release from guinea pig hippocampus by sigma2 receptors.

The binding profile of the sigma2 receptor ligand endo-N-(8-methyl-8-azabicyclo[3.2.1.

Regulation of [3H] dopamine release from mesolimbic and mesocortical areas of guinea pig brain by sigma receptors.

The role of sigma (sigma) receptors in brain function is poorly defined. They are located in limbic areas, including nucleus accumbens (NAC) and prefrontal cortex (PFC), both of which are thought to be involved in schizophrenia. Many antipsychotics (APs), including haloperidol, bind with high affinity to sigma receptors.

sigma1 Receptors in rat striatum regulate NMDA-stimulated [3H]dopamine release via a presynaptic mechanism.

The role of the sigma1 receptor in the regulation of N-methyl-D-aspartate (NMDA)-stimulated [3H]dopamine release from rat striatal slices was examined. The sigma receptor agonist 1S,2R-(--)-N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)cy clohexylamine (BD737) inhibited stimulated release in a concentration-dependent manner. The sigma1 receptor antagonist, 1-(cyclopropylmethyl)-4-(2'-(4"-fluorophenyl)-2'-oxoethyl)piperidi ne HBr (DuP 734), reversed inhibition of release by BD737.

Functional and binding properties of sigma receptors in rat cerebellum.

Autoradiographic studies have shown that sigma receptors are enriched in the locus coeruleus, the origin of noradrenergic projections to the cerebellum, as well as in the Purkinje, molecular, and granular layers and the interpositus cerebellar nucleus of the cerebellum itself. In contrast, the cerebellum is relatively poor in phencyclidine (PCP) binding sites, which have been historically confused with sigma sites. The high ratio of sigma to PCP receptors in cerebellum is advantageous for discriminating sigma-mediated physiological effects.

Sigma receptor regulation of norepinephrine release from rat hippocampal slices.

Multiple sigma receptor subtypes have been identified in the hippocampus, yet their physiological role remains largely undefined. In the current study, we examined the role of sigma receptors in the regulation of N-methyl-D-aspartate (NMDA)-stimulated [3H]norepinephrine ([3H]NE) release from rat hippocampal slices. Both sigma agonists (+)pentazocine and BD737 inhibited stimulated norepinephrine release in a concentration-dependent manner.