Nitric oxide mediation of cardiac receptor reflex responses in the pregnant rat

T. Hines, S. W. Mifflin

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


OBJECTIVES: Our purpose was to determine the contribution of centrally released nitric oxide to baseline sympathetic tone and reflex cardiovascular responses to cardiac stretch in the pregnant rat. STUDY DESIGN: Baseline blood pressure and renal sympathetic nerve activity and reflex changes in these variables in response to intraatrial saline solution injections were measured in anesthetized pregnant (n = 24) and virgin (n = 27) rats before and after bilateral microinjection of L-nitroarginine methyl ester (0.01 to 1 μmol) into the dorsal medulla. Data were analyzed with use of nonparametric analysis of variance. RESULTS: L-Nitroarginine methyl ester microinjection altered basal blood pressure and sympathetic nerve activity (p < 0.05) in virgin but not pregnant rats. L-Nitroarginine methyl ester significantly and equivalently attenuated the reflex sympathoinhibitory and depressor responses to cardiac stretch for 40 minutes in pregnant and virgin animals. CONCLUSION: Central nitric oxide does not modulate basal sympathetic tone in the pregnant rat but is released in the medulla in response to cardiac stretch and plays a role in reflex cardiovascular responses similar to that in virgin rats.

Original languageEnglish
Pages (from-to)1502-1508
Number of pages7
JournalAmerican Journal of Obstetrics and Gynecology
Issue number6
StatePublished - 1997


  • Nucleus tractus solitarii
  • Sympathetic nerve activity


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