Central neocortex

Outside of the hypothalamus, an abundant presence of CRF neurons is found in the neocortex, likely influencing cognitive appraisals and behavioral reactions to stress. High densities of CRF neurons are also found in the central nucleus of the amygdala (CeA), which is the key structure in the mediation of emotion (LeDoux, 2000). These CRF neurons likely modulate affective stress responses. The CRF neurons originating from the CeA project directly and indirectly, via the bed nucleus of the stria terminalis (BNST), to the hypothalamic PVN and influence endocrine responses to stress. Fur-... 

In the peripheral (Wessler 1989) as well as central (Wonnacott 1997) nervous system, presynaptic nicotinic autoreceptors were reported to control the release of acetylcholine. In both locations, the consequence of presynaptic nAChR activation most commonly is an increase in both spontaneous and evoked acetylcholine release (MacDermott et al. 1999), whereas presynaptic muscarinic receptors mediate the opposite effect, an autoinhibition. Recent studies have focused on the composition of presynaptic nAChRs (Table 2). In the hippocampus, nicotinic autoreceptors were suggested to be a3/p4 receptors (Tani et al. 1998), but a role of p2 subunits has also been implicated (Lloyd et al. 1998). Likewise, in the neocortex, presynaptic nicotinic autoreceptors are likely to be 04/ p2 receptors (Marchi et al. 2002). In contrast, in the interpeduncular nucleus the autoreceptors were suggested to mainly contain a3 and p4 subunits (Grady et al. 2001). 

Among the seven families of serotonin receptors, only the 5-HT3 receptors are ligand-gated ion channels, whereas all others are G protein-coupled receptors (Barnes and Sharp 1999). 5-HT3 receptors are rather unselective cation channels with a high permeability for Ca2+ (Ronde and Nichols 1998). In the central nervous system, they are expressed abundantly in the neocortex, the anterior olfactory nucleus, the hippocampus, and the amygdala. In addition, 5-HT3 receptors are present in the caudate putamen and the nucleus accumbens, and, at high levels, in the brain stem (Parker et al. 1996 Morales et al. 1998 Chameau and van Hooft 2006). 

Figure 3.4. Cellular components of the central nervous system. (A) Neurons impregnated with Golgi silver satin, (C) Calbindin immunoreactive intemeurons in the neocortex, (G) astrocytes immunoreactive with an antibody against GFAP, (H) peri-vascular astrocytes components of the BBB, (I) oligodendrocytes and white matter tracts stained with luxol fast blue, (F) ependimal cells around the periventricular zone.

D. (1989) Distribution of cholinergic receptors in the rat and human neocortex. In M. Frotscher and U. Misgeld (Eds.), Central Cholinergic Synapse, Vol. 57, pp. 212-228, Bikhauser Verlag, Boston. 

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