Efferent projections of CGRP/Calca‐expressing parabrachial neurons in mice

Abstract

The parabrachial nucleus (PB) is composed of glutamatergic neurons at the midbrainhindbrain junction. These neurons form many subpopulations, one of which expresses Calca, which encodes the neuropeptide calcitonin gene-related peptide (CGRP). This Calca-expressing subpopulation has been implicated in a variety of homeostatic functions, but the overall distribution of Calca-expressing neurons in this region remains unclear. Also, while previous studies in rats and mice have identified output projections from CGRP-immunoreactive or Calca-expressing neurons, we lack a comprehensive understanding of their efferent projections. We began by identifying neurons with Calca mRNA and CGRP immunoreactivity in and around the PB, including populations in the locus coeruleus and motor trigeminal nucleus. Calcaexpressing neurons in the PB prominently express the mu opioid receptor (Oprm1) and are distinct from neighboring neurons that express Foxp2 and Pdyn. Next, we

The physiological control of eating: signals, neurons, and networks

“…The extensive outputs of the rat PB to the BST, amygdala, PAG, hypothalamus, and thalamus have been carefully described by the groups of Saper and Bernard ((827-831, 1122, 1132, 1133, 1139 but also see (1140)). The projections of mouse PB CGRP neurons have recently been described in some detail (769), and conform to those of the corresponding rat PB subdivisions. The origins of some of these outputs are shown in Figure 18C, which highlights the complex overlap they have with PB inputs in the various PB subdivisions.…”

“…for eating behaviors (767). Taking these results together with the fact that the PTSN also receives interoceptive information via VSN (344) and PBl CGRP neurons (769), this key LHA nucleus may help determine whether preferred food items are consumed in response to conflicting interoceptive and exteroceptive information (767).…”

“…CGRP neurons are an important source of PB outputs, and their locations are shown in yellow in all panels. Their locations in the rat PB have been transcribed from (1118,1144), and in the mouse PB from (769,832,1119). Abbreviations are defined in the Abbreviations List.…”

“…v The Effects of Genetically Targeted Manipulations on Parabrachial Function CGRP neurons are located in the PBle, lc, lv and parts of the KF (Fig. 18) (769,832,1118,1119,1144) thereby providing an inviting target for experimental manipulations. A comprehensive series of studies from Palmiter and his colleagues has used this arrangement to reveal a key integrative role for PBl CGRP neurons in controlling various aspects of food intake (826,832,1119,1135,1145,1146).…”

Brain circuits for pain and its treatment

“…In the dMT, including the paraventricular (PVT) and paratenial (PT) thalamic nuclei,  receptor activation decreases glutamatergic transmission between dMT neurons and basal amygdala (BA) and CeL amygdala neurons, resulting in an overall reduction in feedforward activation of CeM neurons (265).  receptors are also expressed by several classes of amygdalar neurons: by some BLA neurons (266) and, more abundantly, by ITC masses and populations of CeA GABAergic neurons, including Cck + neurons and neurons that project to the PAG, in which  receptors regulate both the flow of information within the amygdaloid complex through G protein-coupled inwardly rectifying K+ (GIRK)-mediated hyperpolarization and the release of GABA in downstream targets (36,(267)(268)(269)(270). Note that  receptor expression in the PVT might also mediate the expression of opioid withdrawal symptoms and aversive memory through a PVT-to-NAc circuit (271).…”