GABAA receptor activation at medullary sympathetic neurons contributes to postexercise hypotension

Radhika Kajekar, Chao-Yin Chen, Tatsushi Mutoh, Ann C. Bonham

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

A single bout of exercise results in a postexercise hypotension (PEH) that is accompanied by a reduced baroreflex function. Based on the role of rostral ventrolateral medulla (RVLM) neurons in controlling sympathetic nerve activity (SNA) and blood pressure, the role of γ-aminobutyric acid (GABA) in controlling RVLM neuronal activity, and the reduced baroreflex-SNA relationship during PEH, we determined whether: 1) RVLM neuronal activity is decreased during PEH, 2) GABAA-receptor mechanisms mediate the decrease, and 3) baroreflex control of RVLM activity is reduced. Spontaneously hypertensive rats (SHR) were subjected to 40 min of treadmill or sham exercise (Sham PEH). PEH lasted 10 h in conscious and anesthetized SHR, indicating that the anesthetics did not affect the expression of PEH. Extracellular RVLM neuronal activity having a cardiac and sympathetic rhythm, lumbar SNA, and blood pressure were recorded at rest and during baroreflex function curves. Resting RVLM neuronal activity was lower and was increased to a greater extent by GABAA-receptor antagonism in PEH versus Sham PEH (P < 0.05). Baroreflex control of RVLM neuronal activity operated with a reduced gain (P < 0.05). Thus increased GABA signaling at RVLM neurons may contribute to PEH.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume282
Issue number5 51-5
StatePublished - 2002
Externally publishedYes

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Post-Exercise Hypotension
GABA-A Receptors
Neurons
Baroreflex
Inbred SHR Rats
gamma-Aminobutyric Acid
Blood Pressure
Aminobutyrates
Anesthetics

Keywords

  • Central sympathetic network
  • Exracellular recording
  • Spontaneously hypertensive rats

ASJC Scopus subject areas

  • Physiology

Cite this

GABAA receptor activation at medullary sympathetic neurons contributes to postexercise hypotension. / Kajekar, Radhika; Chen, Chao-Yin; Mutoh, Tatsushi; Bonham, Ann C.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 282, No. 5 51-5, 2002.

Research output: Contribution to journalArticle

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