The gut-to-brain axis for toxin-induced defensive responses

Viral Gastroenteritis: Sickness Symptoms and Behavioral Responses

“…Released serotonin then stimulates vagal afferents, the major peripheral emetic nerves that participate in vomiting, in response to emetic stimuli in the gastrointestinal tract ( 47 ), including rotavirus ( 4 , 8 ) and probably also norovirus. This is further supported by Xie and coworkers’ ( 48 ) reporting that distinct brainstem circuits drive enterotoxin-induced nausea and retching through nerve signaling in response to serotonin release from EC cells. In addition, rotavirus has been shown to stimulate the release of serotonin from human EC cells and activate structures in the CNS involved in nausea and vomiting ( 8 ).…”

Molecular and anatomical characterization of parabrachial neurons and their axonal projections

“…The axonal inputs to specific clusters of PBN neurons are being established, either by retrograde rabies virus tracing studies starting with specific Cre-drivers, e.g., Calca Cre ( Liu et al, 2022 ; Rodriguez et al, 2017 ) or by candidate approaches starting with expression of AAV-DIO-ChR2 into distal sites of Cre-driver mouse lines mice and recording photoactivated currents in specific PBN neurons, e.g., input from Cck or Dbh neurons in the NTS to Calca neurons in the PBN ( Roman et al, 2016 ), Oxt neurons in preoptic area to Oxtr neurons in PBN ( Ryan et al, 2017 ), Slc17a6 or Slc32a1 inputs from BNST to Pdyn and Calca neurons in PBN ( Luskin et al, 2021 ). Many other molecularly defined inputs to different subregions of the lateral PBN have been described, e.g., Tac1 , Tacr1, and Gpr83 from spinal cord ( Choi et al, 2020 ), Gfral and Glp1r from area postrema ( Zhang et al, 2021 ), Calcr and Tac1 from NTS ( Cheng et al, 2020 ; Xie et al, 2022 ), Slc17a6 and Dbh from LC ( Yang et al, 2021 ), Slc6a3 from ventral tegmental area ( Han et al, 2021 ), Slc32a1 from substantia nigra reticulata, Npy and Slc32a1 from arcuate nucleus ( Alhadeff et al, 2018 ; Wu et al, 2009 ); Mc4r from the PVN ( Garfield et al, 2015 ), Htr2a, Prkcd, or Sst, Pdyn, and Crh from CEA ( Cai et al, 2014 ; Douglass et al, 2017 ; Raver et al, 2020 ). In the latter cases, knowing the locations and molecular identity of PBN clusters that they innervate would refine connectivity maps and provide insight into potential functions.…”

Area postrema neurons mediate interleukin-6 function in cancer-associated cachexia

“…In particular, the AP and the neighboring nucleus tractus solitarii (NTS), as well as the PBN and the PVN have previously been implicated in cancer-associated cachexia 17,[27][28][29] . The AP sends direct projections to the PBN and the NTS, and the NTS also directly projects to the PBN as well as the PVN 50,57,70 . Given previous findings that both the PBN 27,50,55,56,[70][71][72] and the PVN 16,73,74 are involved in feeding suppression, it is possible that the AP drives cancer-associated anorexia via the AP→PBN, the AP→NTS→PBN, or the AP→NTS→PVN pathway.…”

“…The AP sends direct projections to the PBN and the NTS, and the NTS also directly projects to the PBN as well as the PVN 50,57,70 . Given previous findings that both the PBN 27,50,55,56,[70][71][72] and the PVN 16,73,74 are involved in feeding suppression, it is possible that the AP drives cancer-associated anorexia via the AP→PBN, the AP→NTS→PBN, or the AP→NTS→PVN pathway.…”