Figure 5.

Summary schema of glutamatergic and GABAergic input into the DMH/PeF and important efferent brain regions implicated in the regulation of panic-like responses. GABAergic and glutamatergic neurons are represented by circles attached to dashed or solid lines, respectively. Sources of GABA include local interneurons, which are tonically driven by glutamatergic input from mPFC (Bard and Mountcastle, 1948) as well as efferent brain regions such as the LS and mPOA (Feldblum et al., 1993; Risold and Swanson, 1997; Thompson and Swanson, 1998; Grob et al., 2003; Molosh et al., 2010). Glutamatergic input which excites the DMH/PeF region appears to arise from afferent sites such as CVOs (e.g. MnPO/OVLT and SFO (Richard and Bourque, 1992; Grob et al., 2003; Molosh et al., 2010)). Afferent targets of the DMH/PeF that are implicated in the regulation of panic-like responses are also listed (Johnson et al., 2008; Chamberlin and Saper, 1994; Thompson et al., 1996; Fontes et al., 2001; Chen et al., 2004). The Group II mGluRs 2 and 3 are predominantly expressed presynpatically (Shigemoto et al., 1997) and they negatively modulate glutamate neurotransmission (Pin and Duvoisin, 1995), acting on postsynaptic NMDAR (Johnson and Shekhar, 2006).

ACTH: adrenocorticotropic hormone; BNST: bed nucleus of the stria terminalis; CVO: circumventricular organ; DMH/PeF: dorsomedial/perifornical hypothalamus; GABA: gamma-aminobutyric acid; Glu: glutamatergic; GluR2: glutamate receptor 2; IML: intermediolateral cell column of spinal cord; LC: locus coeruleus; LS: lateral septum; mPFC: medial prefrontal cortex; mGluR: metabotropic glutamate receptor; MnPO: median preoptic nucleus; mPOA: medial preoptic area; NaLac: sodium lactate; NMDAR: N-methyl-D-aspartic acid receptor; nTS: nucleus of solitary tract; OVLT: organum vasculosum lamina terminalis; PBN: parabrachial nucleus; PVN: paraventricular hypothalamic nucleus; RVLM: rostroventrolateral medulla; SFO: subfornical organ.