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Hypothalamic paraventricular nucleus‐solitary nucleus pathway tonically inhibits respiratory drive
Author(s) -
Wu Mingfei,
Young John K,
Xu Guang,
Bond Jennifer N,
Haxhiu Musa A.,
Mack Serdia O
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a375
Subject(s) - solitary tract , solitary nucleus , respiratory system , medulla oblongata , microinjection , medicine , endocrinology , reflex , control of respiration , nucleus , hypothalamus , medulla , stimulation , chemistry , receptor , biology , neuroscience , central nervous system
The hypothalamic paraventricular nucleus (PVN) is an integrating site for neuronal pathways regulating food intake, energy expenditure, and body weight. It also mediates responses to changes in behavioral state. PVN neurons project to various respiratory‐related sites, including the nucleus tractus solitarius (NTS), which also regulates reflex responses of the gastrointestinal system (GI). The PVN influence on NTS neuronal activity that controls respiratory motor output to chest wall pumping and upper airway dilating muscles is not well established. We examined projections of PVN neurons to the medial NTS (mNTS) region that receives inputs from the GI and the effects of PVN stimulation on respiratory drive following blockade of oxytocin (OT) receptors in the mNTS. Anterograde grade (n=5)and retrograde studies showed that PVN OT‐containing fibers heavily innervate the mNTS. Microinjection of an OT receptor antagonist, [d‐(CH2)5,Tyr(Me)2,Orn8]‐vasotocin (AVT), into this region in anesthetized, bilaterally vagotomized, and mechanically ventilated male rats (n=4) resulted in a 20.8 ± 7.4% increase in diaphragm amplitude above the baseline and a 25.5 ± 8.5 % increase in genioglossus activity. Moreover frequency increased by 13 ± 4 %, which was due to a 16.4% decrease in inspiratory duration. There was a slight reduction (p>0.05) in blood pressure (7%) and heart rate (12%). These findings indicate that PVN OT is a component of the PVN‐NTS pathway that modulates respiratory activity, possibly via GABAergic neurons in the NTS. Funded by NIH NS45859, NINDS/NCRR U54NS39407, HL50527