Mol Psychiatry

Mol Psychiatry. alterations in 5-HT homeostasis due to the conversation of genetic, environmental and gender-related factors, particularly during early critical developmental stages. The development of animal models that may capture the complexity of such interactions promises to afford a powerful tool to elucidate the pathophysiology of impulsive aggression and suicidability, and find new effective therapies for these conditions. treatment with a low dose of 5-HT1A receptor agonist 8-OH-DPAT activates these receptors on Y-amino-butyric-acid (GABA)-ergic interneurons, leading to an indirect increase of the discharge rate of pyramidal neurons in mPFC (Llado-Pelfort et al., 2012). 5-HT2A/2c receptors are also densely distributed in the PFC; 5-HT2A are co-expressed with 5-HT1A in pyramidal cells and parvalbumin (PV)- and calbindin (Mann et al.)-containing GABA-ergic interneurons (Santana et al., 2004). 5-HT2A receptors activation induces depolarization of both cell types (Aghajanian and Sanders-Bush, 2002). Electrophysiologically, in layer V pyramidal cells, synaptic cIAP1 Ligand-Linker Conjugates 11 Hydrochloride events induced by 5-HT2A consist largely of excitatory postsynaptic potentials (EPSPs) although inhibitory postsynaptic potentials (IPSPs) can be recorded due to GABA-ergic interneurons activation (Aghajanian and Sanders-Bush, 2002). The 5-HT2C receptor is usually primarily expressed in the deep layers of the rat mPFC by calcium-binding proteins-positive GABAergic interneurons in rat pyramidal cells (Liu et al., 2007), while its mRNA is usually absent in pyramidal-shaped cells in both human and monkey PFC (Pasqualetti et al., 1999). Activation of 5-HT2C receptors induces neuronal depolarization (Di Giovanni et al., 2008b; 2011). Thus, the pyramidal cell inhibition seen by stimulation of the 5-HT2C receptor is likely due to excitation of PV-positive interneurons in the mPFC (Di Giovanni et al., 2011). The expression of 5-HT2C receptors in the deep layers of the rat mPFC (layers VCVI), suggests that the action of 5-HT2C receptor may modulate the neuronal output in these layers (Liu et al., 2007). Several lines of evidence indicate that this other 5-HT receptors are also expressed in the neocortex. In particular, 5-HT3 receptors are mainly localized in the superficial layers of the cortex and particularly abundant in GABAergic interneurons (Miquel et al., 2002; Morales and Bloom, 1997; Puig et al., 2004; Tecott et al., 1993). With respect to the distribution of other 5-HT receptors in the PFC, 5-HT4 are particularly expressed in superficial layers (Varn?s et al., 2003) and mostly in pyramidal neurons (Lambe et al., 2011); conversely, 5-HT6 are relatively sparse (Marazziti et al., 2012) and mostly localized in the interneurons (Lambe et al., 2011). Finally, 5-HT7 receptors have also been documented in the frontal pole of the neocortex of rodents and humans (Gustafson et al., 1996; To et al., 1995). The function of these receptors in the cortex is still poorly comprehended. 2.1.2. The 5-HT-ergic system in the amygdala cIAP1 Ligand-Linker Conjugates 11 Hydrochloride In all species studied to date, the amygdala features an exceptionally rich 5-HT-ergic innervation, arising mainly from the DRN (Smith and Porrino, 2008); virtually all neuropeptide Y (NPY)-immunoreactive (ir) neurons receive peri-somatic serotonergic innervations (Bonn et al., 2012). 5-HT1A, 5-HT2A expression has been found in both pyramidal cells and cIAP1 Ligand-Linker Conjugates 11 Hydrochloride inhibitory interneurons (Aznar et al., 2003; McDonald and Mascagni, 2007). 5-HT1B receptors are also expressed in different amygdaloid nuclei and their expression increases in rats exposed to aggression only in the basolateral amygdala (Suzuki et al., 2010). The cellular expression of 5-HT2C receptors cIAP1 Ligand-Linker Conjugates 11 Hydrochloride in pyramidal neurons of the amygdala has not been studied yet, but recent evidence shows that NPY mRNA-producing interneurons co-express both 5-HT1A and 5-HT2C mRNAs (Bonn et al., 2012). Although these anatomical findings are difficult to reconcile with the anxiogenic activity of 5-HT2C and the anxiolytic or mixed effects of 5-HT2A and 5-HT1A receptor activation, it is likely that these divergent roles reflect the high complexity of the circuits for emotional regulation, as well as the different patterns of 5-HT receptor neuronal distribution (Holmes, KLHL22 antibody 2008). Of the other 5-HT receptors, 5-HT3, 5-HT4 and 5-HT7 have been shown to be fairly abundant in amygdala (Gustafson et al., 1996; Miquel et al., 2002; Reynolds et al., 1995; Varn?s et al., 2004; Waeber et al., 1994), but their role in behavioral regulation awaits further examination. 2.1.3. The 5-HTergic system in the NAc The NAc receives an extensive, dense innervation.