Endogenous nitric oxide required for an integrative respiratory function in the cat brain.
1. The involvement of nitric oxide (NO) in the respiratory function of the pons was examined by microinjecting NO synthase-related drugs into discrete regions of the pontine respiratory group (PRG) in decerebrate and decerebellate cats. 2. Microinjection of N omega-nitro-L-arginine (L-NNA, inhibitor of NO synthase), but not D-NNA (the inactive enantiomer), significantly prolonged the duration of inspiration in all 10 cats when lung inflation was withheld. 3. The prolongation of inspiration produced by L-NNA was partially reversed in three cats by microinjections of L-arginine (NO synthase substrate) at the same sites. 4. We conclude that endogenous production of NO from L-arginine in the PRG region is involved in the normal function of the pontine pneumotaxic mechanism. These findings provide the first conclusive evidence that endogenous NO formation is involved in the mechanisms associated with respiratory rhythm generation.
Ling
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Department of Physiology, University of Kentucky, Lexington 40536-0084.
Karius
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Fiscus
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Speck
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D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001921:Brain / Q000502:physiology*; D001923:Brain Chemistry / Q000502:physiology; D002415:Cats; D002531:Cerebellum / Q000502:physiology; D003655:Decerebrate State; D005260:Female; D008297:Male; D008845:Microinjections; D009569:Nitric Oxide / Q000378:metabolism*; D019335:Nitroarginine; D011149:Pons / Q000502:physiology; D012119:Respiration / Q000502:physiology*
D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine