Rhythmic activity from transverse brainstem slice of neonatal rat is modulated by nitric oxide.

摘要: We investigated the role of nitric oxide (NO) in modulation respiratory-like activity recorded from hypoglossal rootlets brainstem slices neonatal rats (P0-P8). Sodium nitroprusside (SNP), S-Nitroso-N-acetyl-D,L-penicillamine (SNAP) and diethylamine-NO (DEA-NO), three NO-donors, reversibly increased burst amplitude with inconsistent effects on frequency. Similar were also obtained endogenous substrate synthase (NOS), L-arginine, whereas inactive enantiomer D-arginine had no effect. The NO-trap agent methylene blue significantly depressed both frequency while hemoglobin only amplitude. Furthermore, addition agents attenuated excitatory response to SNP. Inhibiting NOS either N(omega)-Nitro-L-Arginine (L-NNA) or 7-Nitroindazole (7-NI), decreased Histochemical analysis NADPH-diaphorase activity, a marker for NOS, was performed not treated pharmacologically sections newborn rats, perfused situ. Comparison between vitro vivo conditions indicated that maintained slice preparations. Neurons ambiguus nuclei (dorsal division) exhibited granular staining, suggesting presence NADPHd-positive terminals. cytoplasmic staining identified regions connected nucleus (nucleus tractus solitarius, paramedian gigantocellular reticular nuclei). These neurons might be involved nitrergic control activity. Both pharmacological histochemical data suggest NO may reinforce output medullary respiratory network.