Abstract
The aim of this study was to determine whether NO plays a role in the control of heart rate (HR) within the nucleus ambiguus (NA). Experiments were performed in 29 male Wistar rats anaesthetized with urethane. Microinjections of the NO-donor sodium nitroprusside (SNP; 5 mmol) as well as of L-arginine (L-arg; 50 mmol) into functionally identified cardioinhibitory sites within the NA significantly decreased HR (-57.7 +/- 8.4 and -53.8 +/- 3.2 bpm, respectively), whereas the NO-synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) significantly increased HR (+40 +/- 2.7 bpm). Bilateral vagotomy and i.v. injection of atropine (0.5mg/kg) always abolished the HR decrease induced by SNP and L-arg, whereas propranolol did not affect the HR responses. These results demonstrated that NO mechanisms within the NA play a role in the parasympathetic control of the HR.
Lingua originale | Inglese |
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pagine (da-a) | 481-485 |
Numero di pagine | 5 |
Rivista | NeuroReport |
Volume | 11 |
Numero di pubblicazione | 3 |
DOI | |
Stato di pubblicazione | Pubblicato - 2000 |