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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2 Pt 2
|
| pubmed:dateCreated |
1994-9-21
|
| pubmed:abstractText |
Inhibition of neural activity in the caudal ventrolateral pons (A5 area) by microinjection of muscimol (Mus) attenuates (-65%) the carotid sympathetic chemoreflex (SChR) without altering the concomitant activation of the phrenic nerve (PND). The present study, performed in urethan-anesthetized rats, explores the possibility that activation of the noradrenergic (NE) neurons of the A5 area is involved in the SChR. The NE neuron-selective toxin 6-hydroxydopamine (6-OHDA) was microinjected bilaterally into the spinal cord at T2 level (4 micrograms). This dose reduced the SChR by 55% (n = 5) 90 min after injection, while 0.4 microgram of 6-OHDA produced no effect (n = 5). In seven rats that had received 250 micrograms 6-OHDA intracisternally 2 wk before, Mus injections into the A5 area failed to attenuate the SChR. These rats also had a lower resting mean arterial pressure than controls (97 vs. 112 mmHg). Spinal intrathecal injection of alpha-adrenergic receptor antagonists (prazosin, 10 and 20 micrograms) or phentolamine (20 and 40 micrograms) attenuated resting sympathetic nerve discharge (SND) and SChR in a roughly proportional manner (25-40%); the beta-adrenergic antagonist nadolol (10 and 20 microgram(s) intrathecally) attenuated the SChR selectively but modestly (-10%). The results are generally compatible with the hypothesis that A5 NE neurons and particularly their spinal cord projection could play a facilitating role in the SChR. However, clear evidence that A5 cells contribute selectively to sympathoactivation during chemoreceptor stimulation by releasing NE in the spinal cord could not be obtained.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Aug
|
| pubmed:issn |
0002-9513
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
267
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
R519-26
|
| pubmed:dateRevised |
2008-11-21
|
| pubmed:meshHeading |
pubmed-meshheading:8067463-Animals,
pubmed-meshheading:8067463-Carotid Arteries,
pubmed-meshheading:8067463-Chemoreceptor Cells,
pubmed-meshheading:8067463-Injections, Spinal,
pubmed-meshheading:8067463-Male,
pubmed-meshheading:8067463-Neurons,
pubmed-meshheading:8067463-Norepinephrine,
pubmed-meshheading:8067463-Oxidopamine,
pubmed-meshheading:8067463-Pons,
pubmed-meshheading:8067463-Rats,
pubmed-meshheading:8067463-Rats, Sprague-Dawley,
pubmed-meshheading:8067463-Reflex,
pubmed-meshheading:8067463-Spinal Cord,
pubmed-meshheading:8067463-Sympathetic Nervous System,
pubmed-meshheading:8067463-Sympatholytics,
pubmed-meshheading:8067463-Time Factors
|
| pubmed:year |
1994
|
| pubmed:articleTitle |
A5 noradrenergic neurons and the carotid sympathetic chemoreflex.
|
| pubmed:affiliation |
Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville 22908.
|
| pubmed:publicationType |
Journal Article
|