Monosynaptic excitatory connection from the rostral ventrolateral medulla to sympathetic preganglionic neurons revealed by simultaneous recordings | Macquarie University ResearchOnline

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Monosynaptic excitatory connection from the rostral ventrolateral medulla to sympathetic preganglionic neurons revealed by simultaneous recordings

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/181710

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Title: Monosynaptic excitatory connection from the rostral ventrolateral medulla to sympathetic preganglionic neurons revealed by simultaneous recordings
Related: Hypertension research, Vol. 31, Issue 7, (2008), p.1445-1454
DOI: 10.1291/hypres.31.1445
Publisher: Nature Publishing Group
Date: 2008
FoR/RFCD Code(s): 110300 Clinical Sciences
Author/Creator: Oshima, Naoki
Author/Creator: Kumagai, Hiroo
Author/Creator: Onimaru, Hiroshi
Author/Creator: Kawai, Akira
Author/Creator: Pilowsky, Paul M
Author/Creator: Iigaya, Kamon
Author/Creator: Takimoto, Chie
Author/Creator: Hayashi, Koichi
Author/Creator: Saruta, Takao
Author/Creator: Itoh, Hiroshi
Description: To directly investigate whether a monosynaptic connection exists between neurons in the rostral ventrolateral medulla (RVLM) and sympathetic preganglionic neurons (SPNs), we used simultaneous extracellular recordings of RVLM neurons and whole-cell patch-clamp recordings of SPNs at the Th2 level and analyzed them by spike-triggered averaging. We averaged 200 sweeps of membrane potentials in SPN triggered by the spikes in the RVLM neuron. No clear postsynaptic potentials were detected in the averaged wave of SPNs before angiotensin II (Ang II) superfusion, whereas during superfusion with Ang II (6 micromol/L) on the medulla oblongata side alone excitatory postsynaptic potentials (EPSPs) were clearly found in the SPN of 3 out of 10 pairs at 40 +/- 1 ms after the averaged triggering spike in the RVLM neuron. We consider them to be monosynaptic EPSPs, because 1) the averaged EPSPs exhibited a sharp rise time, 2) the onset latency of the averaged EPSPs in the SPNs after the trigger spike in the RVLM was the same as the latency of the antidromic action potentials in the RVLM neurons in response to electrical stimulation of the SPNs, and 3) the amplitude of the averaged EPSPs was over 2 mV. In summary, combining simultaneous recording and spike-triggered averaging allowed us to demonstrate a monosynaptic excitatory connection between a single RVLM neuron and a single SPN in the thoracic spinal cord. Such connections provide the basis for the maintenance of sympathetic tone and the integrative reflex that relays through the RVLM. The results explain the mechanism by which Ang II in the RVLM area increases peripheral sympathetic activity and blood pressure.
Description: 10 page(s)
Subject Keyword: 110300 Clinical Sciences
Subject Keyword: Angiotensin II
Subject Keyword: Brainstem-spinal cord preparation
Subject Keyword: Excitatory postsynaptic potential
Subject Keyword: Spike-triggered averaging
Subject Keyword: Whole-cell patch-clamp technique
Resource Type: journal article
Organisation: Macquarie University. Australian School of Advanced Medicine

Identifier: http://hdl.handle.net/1959.14/181710
Identifier: ISSN:0916-9636
Identifier: mq-rm-2008990596
Language: eng
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