Descending pathways mediating cardiovascular response from dorsomedial hypothalamic nucleus

M. A P Fontes, T. Tagawa, J. W. Polson, S. J. Cavanagh, R. A L Dampney*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

159 Citations (Scopus)

Abstract

Physiological and anatomic methods were used to determine whether neurons in the rostral ventrolateral medulla (RVLM), nucleus tractus solitarius (NTS), or hypothalamic paraventricular nucleus (PVN) mediate the cardiovascular response evoked from the dorsomedial hypothalamic nucleus (DMH), which is believed to play a key role in mediating responses to stress. In urethane-anesthetized rats, activation of neurons in the DMH by microinjection of bicuculline resulted in a large increase in arterial pressure, heart rate, and renal sympathetic nerve activity. The pressor and sympathoexcitatory responses, but not the tachycardic response, were greatly reduced after bilateral muscimol injections into the RVLM even when baseline arterial pressure was maintained at a constant level. These responses were not reduced by muscimol injections into the PVN or NTS. Retrograde tracing experiments identified many neurons in the DMH that projected directly to the RVLM. The results indicate that the vasomotor and cardiac components of the response evoked from the DMH are mediated by pathways that are dependent and independent, respectively, of neurons in the RVLM.

Original languageEnglish
Pages (from-to)H2891-H2901
Number of pages11
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume280
Issue number6 49-6
Publication statusPublished - 2001
Externally publishedYes

Keywords

  • Nucleus tractus solitarius
  • Paraventricular nucleus
  • Rostral ventrolateral medulla
  • Stress

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