Somatic stimulation reveals unique response patterns in different sympathetic nerves in the rat

P. G. R. Burke, Q. Li, J. Neale, S. McMullan, P. M. Pilowsky, A. K. Goodchild

    Research output: Contribution to journalMeeting abstractpeer-review

    Abstract

    The aims of this study were to identify functionally distinct
    efferent projections of RVLM presympathetic neurons by axon
    conduction velocity and catecholamine phenotype. We simultaneously
    recorded the sympathoexcitatory response of multiple,
    sympathetic nerves – cervical, renal and splanchnic – to sciatic nerve
    stimulation (single 0.2 ms pulse, 50 sweeps at 0.5 Hz, 1–50 V), in
    urethane-anaesthetised (1.3 g/kg i.p.), paralysed, vagotomised and
    artificially ventilated Sprague Dawley rats (n= 18). Furthermore,
    splanchnic somatosympathetic responses (SSR) was examined in rats
    treated with intraspinal anti-dopamine-beta-hydroxylase-saporin
    (24 ng/side, n= 8), a neurotoxin that depleted 60–80% of catecholamine
    neurons in the RVLM compared to IgG-saporin control
    (n= 5). We observed qualitatively different SSR responses in all
    nerves. Low intensity (4–15 V) sciatic stimulation evoked biphasic
    responses in the renal and splanchnic nerves and a single early peak
    in the cervical nerve. This stimulus intensity was sufficient to recruit
    fast conducting Aδ fibres recorded in the dorsal root (n= 4). The
    second peak of the splanchnic nerve was eliminated with antidopamine-beta-hydroxylase-saporin
    treatment which spared neurons
    that appear to have higher conduction velocities. The unique
    temporal features of each SSR reveal distinct spinal projections of
    presympathetic RVLM neurons.
    Original languageEnglish
    Article numberP7.22
    Pages (from-to)117-117
    Number of pages1
    JournalAutonomic Neuroscience: Basic and Clinical
    Volume149
    Issue number1-2
    DOIs
    Publication statusPublished - Jun 2009
    Event30th Annual Scientific Meeting of the High-Blood-Pressure-Research-Council-of-Australia - Melbourne, Australia
    Duration: 3 Dec 20085 Dec 2008

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