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Nitric oxide synthesis blockade reduced the baroreflex sensitivity in trained rats.
Auton Neurosci. 2009 Oct 05; 150(1-2):38-44.AN

Abstract

OBJECTIVE

The present study has investigated the effect of blockade of nitric oxide synthesis on cardiovascular autonomic adaptations induced by aerobic physical training using different approaches: 1) double blockade with methylatropine and propranolol; 2) systolic arterial pressure (SAP) and heart rate variability (HRV) by means of spectral analysis; and 3) baroreflex sensitivity.

METHODS

Male Wistar rats were divided into four groups: sedentary rats (SR); sedentary rats treated with N(omega)-nitro-l-arginine methyl ester (L-NAME) for one week (SRL); rats trained for eight weeks (TR); and rats trained for eight weeks and treated with L-NAME in the last week (TRL).

RESULTS

Hypertension and tachycardia were observed in SRL group. Previous physical training attenuated the hypertension in L-NAME-treated rats. Bradycardia was seen in TR and TRL groups, although such a condition was more prominent in the latter. All trained rats had lower intrinsic heart rates. Pharmacological evaluation of cardiac autonomic tonus showed sympathetic predominance in SRL group, differently than other groups. Spectral analysis of HRV showed smaller low frequency oscillations (LF: 0.2-0.75 Hz) in SRL group compared to other groups. Rats treated with L-NAME presented greater LF oscillations in the SAP compared to non-treated rats, but oscillations were found to be smaller in TRL group. Nitric oxide synthesis inhibition with L-NAME reduced the baroreflex sensitivity in sedentary and trained animals.

CONCLUSION

Our results showed that nitric oxide synthesis blockade impaired the cardiovascular autonomic adaptations induced by previous aerobic physical training in rats that might be, at least in part, ascribed to a decreased baroreflex sensitivity.

Authors+Show Affiliations

Exercise Physiology Laboratory of the Department of Biomechanics, Medicine and Rehabilitation, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

19443278

Citation

Souza, Hugo C D., et al. "Nitric Oxide Synthesis Blockade Reduced the Baroreflex Sensitivity in Trained Rats." Autonomic Neuroscience : Basic & Clinical, vol. 150, no. 1-2, 2009, pp. 38-44.
Souza HC, De Araújo JE, Martins-Pinge MC, et al. Nitric oxide synthesis blockade reduced the baroreflex sensitivity in trained rats. Auton Neurosci. 2009;150(1-2):38-44.
Souza, H. C., De Araújo, J. E., Martins-Pinge, M. C., Cozza, I. C., & Martins-Dias, D. P. (2009). Nitric oxide synthesis blockade reduced the baroreflex sensitivity in trained rats. Autonomic Neuroscience : Basic & Clinical, 150(1-2), 38-44. https://doi.org/10.1016/j.autneu.2009.04.007
Souza HC, et al. Nitric Oxide Synthesis Blockade Reduced the Baroreflex Sensitivity in Trained Rats. Auton Neurosci. 2009 Oct 5;150(1-2):38-44. PubMed PMID: 19443278.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Nitric oxide synthesis blockade reduced the baroreflex sensitivity in trained rats. AU - Souza,Hugo C D, AU - De Araújo,João E, AU - Martins-Pinge,Marli C, AU - Cozza,Izabela C, AU - Martins-Dias,Daniel P, Y1 - 2009/05/13/ PY - 2008/09/12/received PY - 2009/03/16/revised PY - 2009/04/20/accepted PY - 2009/5/16/entrez PY - 2009/5/16/pubmed PY - 2009/11/17/medline SP - 38 EP - 44 JF - Autonomic neuroscience : basic & clinical JO - Auton Neurosci VL - 150 IS - 1-2 N2 - OBJECTIVE: The present study has investigated the effect of blockade of nitric oxide synthesis on cardiovascular autonomic adaptations induced by aerobic physical training using different approaches: 1) double blockade with methylatropine and propranolol; 2) systolic arterial pressure (SAP) and heart rate variability (HRV) by means of spectral analysis; and 3) baroreflex sensitivity. METHODS: Male Wistar rats were divided into four groups: sedentary rats (SR); sedentary rats treated with N(omega)-nitro-l-arginine methyl ester (L-NAME) for one week (SRL); rats trained for eight weeks (TR); and rats trained for eight weeks and treated with L-NAME in the last week (TRL). RESULTS: Hypertension and tachycardia were observed in SRL group. Previous physical training attenuated the hypertension in L-NAME-treated rats. Bradycardia was seen in TR and TRL groups, although such a condition was more prominent in the latter. All trained rats had lower intrinsic heart rates. Pharmacological evaluation of cardiac autonomic tonus showed sympathetic predominance in SRL group, differently than other groups. Spectral analysis of HRV showed smaller low frequency oscillations (LF: 0.2-0.75 Hz) in SRL group compared to other groups. Rats treated with L-NAME presented greater LF oscillations in the SAP compared to non-treated rats, but oscillations were found to be smaller in TRL group. Nitric oxide synthesis inhibition with L-NAME reduced the baroreflex sensitivity in sedentary and trained animals. CONCLUSION: Our results showed that nitric oxide synthesis blockade impaired the cardiovascular autonomic adaptations induced by previous aerobic physical training in rats that might be, at least in part, ascribed to a decreased baroreflex sensitivity. SN - 1872-7484 UR - https://www.unboundmedicine.com/medline/citation/19443278/Nitric_oxide_synthesis_blockade_reduced_the_baroreflex_sensitivity_in_trained_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1566-0702(09)00121-0 DB - PRIME DP - Unbound Medicine ER -