Role of the paraventricular nucleus in the reflex diuresis to pulmonary lymphatic obstruction in rabbits.
The changes in urine flow and renal sympathetic nerve activity (RSNA) due to pulmonary lymphatic obstruction (PLO) were examined in anesthetized, artificially ventilated New Zealand white rabbits. PLO was produced by pressurizing an isolated pouch created in the right external jugular vein at the points of entry of the right lymphatic ducts. During this maneuver, urine flow increased from 8.5 ± 0.3 mL/10 min to 12 ± 0.5 mL/10 min (P < 0.0001) and RSNA increased from 24.0 ± 4 to 40.0 ± 5 μV·s (P < 0.0001). Bilateral lesioning of the paraventricular nucleus (PVN) of the hypothalamus or cervical vagotomy abolished these responses. PLO increased c-fos gene expression in the PVN. The increase in urine flow due to PLO was attenuated by muscimol and abolished by kynurenic acid microinjections into the PVN. The results show that (i) neurons in the PVN are an important relay site in the reflex arc, which is activated by PLO; and (ii) this activation is regulated by glutamatergic and partly by GABAergic input to the PVN.
a Department of Physiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
Rishabh Charan
RC
Choudhary
a Department of Physiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
Ravindra Kumar
RK
Sharma
b Department of Pharmacology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
Kavita
K
Gulati
a Department of Physiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
Krishnan
K
Ravi
D000818:Animals; D004195:Disease Models, Animal; D004231:Diuresis / Q000187:drug effects / Q000502:physiology*; D015870:Gene Expression; D016762:Genes, fos; D007668:Kidney / Q000294:innervation; D007736:Kynurenic Acid / Q000008:administration & dosage; D008171:Lung Diseases / Q000235:genetics / Q000503:physiopathology*; D008206:Lymphatic Diseases / Q000235:genetics / Q000503:physiopathology*; D042601:Lymphatic Vessels / Q000503:physiopathology; D008845:Microinjections; D009118:Muscimol / Q000008:administration & dosage; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000503:physiopathology*; D011817:Rabbits; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D013564:Sympathetic Nervous System / Q000503:physiopathology; D014628:Vagotomy
D009118:Muscimol; D007736:Kynurenic Acid
GABA; glutamate; hypothalamus; kidney; lung; lymphatics; nerf vague; poumon; rein; vagus; vaisseaux lymphatiques