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Volume 3
Journal of Nursing Research and Practice
Nursing and Heart 2019
April 22-23, 2019
Nursing Education and Evidence Based Practice Conference
Heart Conference
April 22-23, 2019 Dubai, UAE
World
4
th
International
&
Neural regulation of cardiovascular function during inhibition of nitric oxide synthesis in rats
Meenakshi Chaswal, Shobha Das, Jagdish Prasad, Anju Katyal
and
Mohammad Fahim
Vardhman Mahavir Medical College, India
D
eficient synthesis of Nitric Oxide (NO) is an important component not only of hypertension but also of cardiac autonomic
dysfunction. It is not known whether the hemodynamic and cardiac autonomic derangements associated with NO deficiency are
due to interference of direct vasodilatory action of NO or involve some neuro-humoral system. In order to clarify and fill in the existing
gaps, we assessed cardiac autonomic functions during acute and chronic inhibition of NO synthesis by NG-nitro-L-arginine methyl
ester (L-NAME) in adult Wistar rats. Baroreflex Sensitivity (BRS) and Heart Rate Variability (HRV) were measured for assessment of
cardiac autonomic functions. We further evaluated the contribution of oxidative stress, sympathetic nervous system as well as renin-
angiotensin system, to the changes in neural regulation of cardiovascular system during NO inhibition. Serum Malondialdehyde
(MDA) was measured as a marker of oxidative stress. “Subtractive approach” of chemical sympathectomy by 6-hydroxydopamine
was used to study the role of sympathetic nervous system and extent of involvement of renin-angiotensin system was studied using
angiotensin II type I receptor blocker, losartan. Our results reveal that sympathectomy completely reversed not only pressure rise but
also cardiac autonomic dysfunction in chronic L-NAME treated rats whereas a partial reversal that too of only cardiac autonomic
responses was observed in acute L-NAME treated rats. These results thus suggest that, it is the inhibition of direct vasorelaxant action
of NO which mediates the effects seen after acute L-NAME administration on the other hand, effects of long-term inhibition of NO
synthesis are primarily mediated through sympathoexcitation. Thus, the role of sympathetic nervous system in L-NAME model
is time dependent and its contribution becomes important with longer NO inhibition. In addition, administration of losartan had
no effect on pressor response of L-NAME irrespective of its duration, but it was effective in restoration of autonomic derangement
especially after chronic L-NAME treatment.
balachandranmeenakshi@ymail.comJ Nursing Research and Practice, Volume 3
DOI: 10.4172/2632-251X-C3-009