-
- G Hedo and J A Lopez-Garcia.
- Departamento Fisiologia, Edificio de Medicina, Universidad de Alcala, Alcala de Henares, 28871, Madrid, Spain.
- Neuropharmacology. 2001 Dec 1; 41 (7): 862-9.
AbstractThe rat hemisected spinal cord preparation was used to assess the role of different adrenoceptor subtypes on the modulation of nociceptive reflexes. These were elicited by trains of high intensity electrical stimuli delivered to a lumbar dorsal root. Responses were recorded from the corresponding ventral root in AC- and DC-amplification modes simultaneously. Superfusion of noradrenaline produced a potentiation of action potential firing (AC channel) as well as a depression of the cumulative depolarisation (DC channel) in responses to repetitive afferent stimulation.Noradrenaline-induced potentiation of firing was mimicked by the alpha1A-adrenoceptor agonist A 61603 and the alpha1-adrenoceptor agonist methoxamine in a reversible and concentration-dependent manner. The order of potency of these agonists was A61603>noradrenaline>methoxamine. The alpha(1A)-adrenoceptor antagonist 5-methyl-urapidil and the alpha1-adrenoceptor antagonist corynanthyne blocked the excitatory effects of noradrenaline. In contrast, the alpha(1B/D)-adrenoceptor antagonists chloroethylclonidine and BMY 7378 failed to block this effect.Noradrenaline-induced depression of cumulative depolarisation was mimicked by the alpha2-adrenoceptor agonist UK 14,304. In addition, this compound produced inhibition of firing in responses to afferent stimulation. These results show that noradrenaline has bi-directional modulatory effects on nociceptive reflexes and indicate that selective activation of alpha1A- but not alpha1B/D-adrenoceptors mediate potentiation of spinal nociceptive reflexes.
Notes
Knowledge, pearl, summary or comment to share?You can also include formatting, links, images and footnotes in your notes
- Simple formatting can be added to notes, such as
*italics*
,_underline_
or**bold**
. - Superscript can be denoted by
<sup>text</sup>
and subscript<sub>text</sub>
. - Numbered or bulleted lists can be created using either numbered lines
1. 2. 3.
, hyphens-
or asterisks*
. - Links can be included with:
[my link to pubmed](http://pubmed.com)
- Images can be included with:
![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
- For footnotes use
[^1](This is a footnote.)
inline. - Or use an inline reference
[^1]
to refer to a longer footnote elseweher in the document[^1]: This is a long footnote.
.