Preliminary evidence of altered sensitivity to benzodiazepines as a function of maternal care in the rat.

Variations in maternal care over the first week of life alter the expression of genes encoding for various subunits of the GABA(A)/benzodiazepine (BZ) receptor in the amygdala, a brain region associated with fear behavior. Increased maternal licking/grooming and arched-back nursing are associated with decreased fearfulness and enhanced expression of the subunits that confer BZ sensitivity. In these studies we found that the offspring of high licking/grooming-arched-back nursing mothers also showed increased behavioral sensitivity to acute BZ treatment, suggesting a functional relation between the effect on gene expression and fear behavior.

GABAA receptor epsilon subunit expression in identified peptidergic neurons of the rat hypothalamus.

Dual-labeling immunohistochemical or in situ hybridization studies for the recently cloned epsilon-subunit and several neuropeptides were performed in the rat hypothalamus. We revealed an extensive co-expression (>90%) with hypocretin (Hcrt), oxytocin (OT), the gonadotropin-releasing hormone (GnRH), and the melanin-concentrating hormone (MCH) peptides, whereas occasional co-expression (<10%) with cocaine-amphetamine-regulated transcript (CART) was found. Our results suggest that novel GABA(A) receptor subtypes comprising epsilon-subunit are important for metabolic and neuroendocrine functions.

Localisation of GABA(A) receptor epsilon-subunit in cholinergic and aminergic neurones and evidence for co-distribution with the theta-subunit in rat brain.

In situ hybridisation and immunohistochemical methodologies suggest the existence of a large diversity of GABA(A) receptor subtypes in the brain. These are hetero-oligomeric proteins modulated by a number of clinically important drugs, depending on their subunit composition. We recently cloned and localised the rat GABA(A) receptor epsilon-subunit by in situ hybridisation and immunohistochemical procedures.

cDNA cloning and expression of a gamma-aminobutyric acid A receptor epsilon-subunit in rat brain.

A cDNA encoding a GABA(A) receptor subunit was isolated from rat brain. The predicted protein is 70% identical to the human epsilon-subunit. It was recently reported [Sinkkonen et al.