Single-cell quantitative expression of nicotinic acetylcholine receptor mRNA in rat hippocampal interneurons.

Hippocampal interneurons are a very diverse population of cells. Using single-cell quantitative PCR to analyze rat CA1 hippocampal interneurons, we quantified neuronal nicotinic acetylcholine receptor (nAChR) mRNA subunit expression and detailed possible nAChR subtype combinations for the α2, α3, α4, α5, α7, β2, β3, and β4 subunits. We also compared the expression detected in the stratum oriens and the stratum radiatum hippocampal layers.

α6 subunit-containing nicotinic receptors mediate low-dose ethanol effects on ventral tegmental area neurons and ethanol reward.

Dopamine (DA) neuron excitability is regulated by inhibitory GABAergic synaptic transmission and modulated by nicotinic acetylcholine receptors (nAChRs). The aim of this study was to evaluate the role of α6 subunit-containing nAChRs (α6*-nAChRs) in acute ethanol effects on ventral tegmental area (VTA) GABA and DA neurons. α6*-nAChRs were visualized on GABA terminals on VTA GABA neurons, and α6*-nAChR transcripts were expressed in most DA neurons, but only a minority of VTA GABA neurons from GAD67 GFP mice.

Pax3 isoforms in sensory neurogenesis: expression and function in the ophthalmic trigeminal placode.

Background: In the trigeminal placode, Pax3 is classified as necessary but not sufficient for sensory neuron differentiation. One hypothesis is that different Pax3 isoforms regulate cellular differentiation uniquely. Pax3 is known to sometimes activate and sometimes repress gene transcription, and its activity can be dependent on the isoforms present.

Acute and chronic ethanol modulate dopamine D2-subtype receptor responses in ventral tegmental area GABA neurons.

Background: Ventral tegmental area (VTA) gamma-aminobutyric acid (GABA) neurons appear to be critical substrates underlying the acute and chronic effects of ethanol on dopamine (DA) neurotransmission in the mesocorticolimbic system implicated in drug reward. VTA GABA neuron firing rate is reduced by acute ethanol and enhanced by DA via D2 receptor activation. The objective of this study was to evaluate the role of D2 receptors in acute ethanol inhibition of VTA GABA neuron activity, as well as the adaptation of D2 receptors by chronic ethanol consumption.

Connexin-36 gap junctions mediate electrical coupling between ventral tegmental area GABA neurons.

Communication between neurons in the mammalian brain is primarily through chemical synapses; however, evidence is accumulating in support of electrical synaptic transmission between some neuronal types in the mature nervous system. The authors have recently demonstrated that the gap junction (GJ) blocker quinidine suppresses stimulus-induced and dopamine-evoked coupling of gamma amino butyric acid (GABA) neurons in the ventral tegmental area (VTA) of mature rats (Stobbs et al., 2004).

Serotonin 5-HT(3) receptors in rat CA1 hippocampal interneurons: functional and molecular characterization.

The molecular makeup of the serotonin 5-HT(3) receptor (5-HT(3)R) channel was investigated in rat hippocampal CA1 interneurons in slices using single-cell RT-PCR and patch-clamp recording techniques. We tested for the expression of the 5-HT(3A) (both short and long splice variants) and 5-HT(3B) subunits, as well as the expression of the alpha4 subunit of the neuronal nicotinic ACh receptors (nAChRs), the latter of which has been shown to co-assemble with the 5-HT(3A) subunit in heterologous expression systems. Both the 5-HT(3A)-short and alpha4-nAChR subunits were expressed in these interneurons, but we could not detect any expression of either the 5-HT(3B) or the 5-HT(3A)-long subunits.

Rat nicotinic ACh receptor alpha7 and beta2 subunits co-assemble to form functional heteromeric nicotinic receptor channels.

Rat hippocampal interneurons express diverse subtypes of functional nicotinic acetylcholine receptors (nAChRs), including alpha7-containing receptors that have properties unlike those expected for homomeric alpha7 nAChRs. We previously reported a strong correlation between expression of the alpha7 and of the beta2 subunits in individual neurons. To explore whether co-assembly of the alpha7 and beta2 subunits might occur, these subunits were co-expressed in Xenopus oocytes and the functional properties of heterologously expressed nAChRs were characterized by two-electrode voltage clamp.