Jacobsen_2012_Neurosci.Lett_515_7

The dominant nicotine acetylcholine receptor (nAChR) subtype in the brain is the pentameric receptor containing both alpha4 and beta2 subunits (alpha4beta2). Due to the lack of selective agonists it has not been ruled out what neuronal circuits that are stimulated after systemic administration with nicotine. We used the novel and selective alpha4beta2 receptor agonist ispronicline (10 and 30 mg/kg s.c.) to localise the activated neurons in the rat forebrain using c-Fos-immunoreactivity as a marker of immediate neuronal activity. In the hypothalamic paraventricular nucleus, a large increase of c-Fos-positive cells was found only within its medial part. In addition, an increased number of c-Fos-immunoreactive cells were observed in the central nucleus of the amygdala, and the dorsolateral part of the bed nucleus of the stria terminalis. The restricted distribution of c-Fos to these areas, all of which are directly or indirectly involved in acute stress regulation after a single dose of ispronicline, supports earlier studies that the alpha4beta2 receptors are strongly involved in nicotine-dependent activation of the hypothalamo-pituitary adrenocortical axis.