c-fos identifies GABA-synthesizing barosensitive neurons in caudal ventrolateral medulla

Jane B. Minson*, Ida J. Llewellyn-Smith, John P. Chalmers, Paul M. Pilowsky, Leonard F. Arnolda

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    40 Citations (Scopus)

    Abstract

    HYPERTENSION in the conscious rat, elicited by i.v. infusion of phenylephrine, evoked expression of the immediate early gene c-fos in discrete groups of brain stem neurons. Fos-immunoreactive neurons were located in the caudal ventrolateral medulla (CVLM); others were located in the nucleus of the tractus solitarius (NTS). Because of their sensitivity to alterations in arterial pressure, these neurons are likely to subserve the arterial baroreceptor reflex. The aim of this study was to identify the brain stem projections and the neurotransmitter content of the barosensitive CVLM neurons using neuronal tracing and immunohistochemistry. Some of the barosensitive CVLM neurons projected directly tO the rostral ventrolateral medulla (RVLM), and many contained the GABA synthesizing enzyme, glutamic acid decarboxylase (GAD). Other CVLM neurons, containing markers of glutamate or catecholamine synthesis, were insensitive to baroreceptor stimulation. This study delineates neuronal pathways acting in the arterial baroreceptor reflex and identifies precisely GABA-synthesizing CVLM neurons as the source of inhibitory input to the RVLM.

    Original languageEnglish
    Pages (from-to)3015-3021
    Number of pages7
    JournalNeuroReport
    Volume8
    Issue number14
    Publication statusPublished - 1997

    Keywords

    • Baroreceptor reflex
    • Blood pressure
    • Fos
    • GAD
    • Retrograde tracing
    • Rostral ventrolateral medulla

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