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The present study investigated the role of corticotropin-releasing hormone (CRH) in the lateral parabrachial nucleus (LPBN) in the behavioral control of body fluid homeostasis by determining the effect of bilateral injections of the CRH receptor antagonist, [alpha]-helical corticotropin-releasing factor [(CRF).sub.9-41], and the CRH receptor agonist, CRH, on sodium chloride (salt appetite) and water (thirst) intake. Groups of adult, male Sprague-Dawley rats had stainless-steel cannulas implanted bilaterally into the LPBN and were sodium depleted or water deprived. Bilateral injections of [alpha]-helical [CRF.sub.9-41] into the LPBN significantly potentiated water and salt intake in the sodium-depleted rats when access to fluids was restored. Bilateral injections of [alpha]-helical [CRF.sub.9-41] into the LPBN (1.0 [micro]g) also increased sodium appetite in water-deprived rats. Conversely, in sodium-depleted animals, bilateral injections of CRH inhibited sodium chloride intake. These results suggest that there is an endogenous CRH inhibitory mechanism operating in the LPBN to modulate the intake of sodium (salt appetite). This mechanism may contribute to the behavioral control of restoration of body fluid homeostasis in sodium-deficient states. water intake; [alpha]-helical corticotropin-releasing factor

Cowley, Elizabeth A., Karuthapillai Govindaraju, Claudine Guilbault, Danuta Radzioch, and David H. Eidelman. Airway surface liquid composition in mice. Am J Physiol Lung Cell Mol Physiol 278: L1213-L1220, 2000.--Airway surface liquid (ASL) lines the conducting airways of the respiratory tract. We collected small samples of this liquid from the lower tracheae of anesthetized C57BL/6 mice and determined its ionic composition (in mM: 87.2 [Na.sup.+], 4.7 [K.sup.+], and 57.0 [Cl.sup.-]). Intravenous methacholine produced significant increases in the concentrations of [Na.sup.+], [K.sup.+], and [Cl.sup.-] within ASL. A limited analysis of liquid from cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice revealed no significant differences compared with littermate controls; however, Pseudomonas aeruginosa infection led to an increase in the salt concentration of ASL in cftr(+/+) mice. Morphometric measurements of tracheal submucosal gland volume revealed significant differences between inbred mouse strains, corresponding to ease of ASL collection. We conclude that although submucosal glands may be responsible for the production of some ASL, the ionic composition of this liquid is actively regulated by the underlying epithelial cells. Pseudomonas aeruginosa; cystic fibrosis; submucosal gland