Neurons of rostral ventrolateral medulla mediate somatic pressor reflex

R. L. Stornetta, Shaun Morrison, D. A. Ruggiero, D. J. Reis

Research output: Contribution to journalArticle

120 Citations (Scopus)

Abstract

The somatic pressor reflex (SPR) elicited in anesthetized paralyzed rats by electrical stimulation of the sciatic or sural cutaneous afferent nerves produced an increase in arterial pressure ranging from 5 to 40 mmHg. Stimulation of femoral or tibial afferent nerves from muscle produced a depressor response. The SPR was not affected by midpontine transection but was eliminated either by hemisection of the lumbar spinal cord contralateral, but not ipsilateral, to the stimulated nerve or by electrolytic or kainic acid lesion of the contralateral, but not ipsilateral, rostral ventrolateral medulla (RVL). Stimulation of the brachial plexus elicited an SPR that was not eliminated by contralateral lumbar hemisection but was abolished by RVL lesion. RVL lesions consistently overlapped areas containing phenylethanolamine N-methyltransferase-labeled C1 adrenergic neurons. Kainic acid injections into the lateral reticular nucleus (LRN) did not affect the SPR. Neither contralateral nor ipsilateral electrolytic lesions of other autonomic areas including parabrachial nucleus, the nucleus tractus solitarii, the A5 region, or the inferior cerebellar peduncle (output pathway of the LRN) affected the reflex. In axonal transport studies using horseradish peroxidase, afferent terminals of the sciatic nerve were shown to overlap spinoreticular neurons in the dorsal horn retrogradely labeled from tracer injections in the RVL. We conclude that the SPR can be elicited in rats, that it is mediated by spinoreticular afferents traveling in the contralateral spinal cord, and that the C1 adrenergic area of the RVL is a critical region for the integration of the somatic pressor reflex.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume256
Issue number2
StatePublished - 1989
Externally publishedYes

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Reflex
Neurons
Spinal Cord
Kainic Acid
Phenylethanolamine N-Methyltransferase
Posterior Horn Cells
Adrenergic Neurons
Tibial Nerve
Injections
Axonal Transport
Solitary Nucleus
Brachial Plexus
Sciatic Nerve
Horseradish Peroxidase
Thigh
Adrenergic Agents
Electric Stimulation
Arterial Pressure
Muscles
Skin

ASJC Scopus subject areas

  • Physiology

Cite this

Neurons of rostral ventrolateral medulla mediate somatic pressor reflex. / Stornetta, R. L.; Morrison, Shaun; Ruggiero, D. A.; Reis, D. J.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 256, No. 2, 1989.

Research output: Contribution to journalArticle

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