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Bianchi-da-Silva LM, Menescal-de-Oliveira L, Hoffmann A. Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas. J Auton Nerv Syst. 2000;80(1):31-9doi: 10.1016/s0165-1838(99)00083-1.
Bianchi-da-Silva, L. M., Menescal-de-Oliveira, L., & Hoffmann, A. (2000). Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas. Journal of the autonomic nervous system, 80(1), 31-9. https://doi.org/10.1016/s0165-1838(99)00083-1
Bianchi-da-Silva, L M, et al. "Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas." Journal of the autonomic nervous system vol. 80,1 (2000): 31-9. doi: https://doi.org/10.1016/s0165-1838(99)00083-1
Bianchi-da-Silva LM, Menescal-de-Oliveira L, Hoffmann A. Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas. J Auton Nerv Syst. 2000 Apr 12;80(1):31-9. doi: 10.1016/s0165-1838(99)00083-1. PMID: 10742537.
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J Auton Nerv Syst. 2000 Apr 12;80(1):31-9. doi: 10.1016/s0165-1838(99)00083-1.

Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas.

Journal of the autonomic nervous system

L M Bianchi-da-Silva, L Menescal-de-Oliveira, A Hoffmann

Affiliations

  1. Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, 14 049-900 Ribeirão Preto, São Paulo, Brazil.

PMID: 10742537 DOI: 10.1016/s0165-1838(99)00083-1

Abstract

Systemic injection of sodium nitroprusside (30 microg/kg, i.v.) in the awake Bufo paracnemis toad induced a fall in arterial blood pressure and tachycardia. This tachycardia, but not the hypotension, was significantly reduced in toads with bilateral electrolytic lesion of the caudal and commissural regions of the solitary tract nucleus and in animals with transection of the spinal cord, 2 mm below the obex. This indicates that the tachycardia is reflex, depends on the integrity of the solitary tract nucleus and is due to descending spinal autonomic activation. Pretreatment with propranolol (4 mg/kg, i.v.) significantly reduced the tachycardia but did not block it completely, showing the importance of beta-adrenoceptors in its genesis. The reflex increase in heart rate induced by nitroprusside was not statistically significant in animals with bilateral section of the laryngeal nerve, whose baroreceptor fibers originate from the pulmocutaneous artery or in animals in which the bilateral section of the laryngeal nerve was performed together with section of the glossopharyngeal nerves, which incorporate fibers originating from the carotid labyrinth. The reduction of the reflex tachycardia was significant in toads with aortic arch denervation alone or combined with section of the laryngeal nerves or in animals with complete denervation of the three baroreceptors areas. These results suggest that the region of the aortic arch, when submitted to unloading, is the most important baroreceptor zone for cardiac compensation in toads.

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