Abstract
DALA is a synthetic pentapeptide that produces inhibition of the tail-flick reflex evoked by radiant heat, as well as hypotension and bradycardia. Two experiments examined the effects of administration of various receptor antagonists into the subarachnoid space of the lumbar spinal cord on the antinociception produced by IV administration of DALA. Experiment 1 showed that intrathecal administration of 30 μg of phentolamine produced a significant reduction in the antinociceptive effect of DALA, while naloxone (30 μg), methysergide (30 μg), or vehicle control had no effect. Experiment 2 showed that intrathecal administration of combinations of either phentolamine and methysergide, or phentolamine and naloxone, were no more effective in reducing the antinociceptive effect of DALA than administration of phentolamine alone. These data demonstrate the involvement of descending noradrenergic systems in the production of antinociception by IV DALA. Further, they indicate that the antinociception produced by DALA is independent of a direct spinal action of the drug.
Original language | English (US) |
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Pages (from-to) | 65-72 |
Number of pages | 8 |
Journal | Pharmacology, Biochemistry and Behavior |
Volume | 30 |
Issue number | 1 |
DOIs | |
State | Published - May 1988 |
Externally published | Yes |
Keywords
- Antinociception
- Cardiovascular
- DALA
- Intrathecal
- Pain
- Vagus
ASJC Scopus subject areas
- Biochemistry
- Toxicology
- Pharmacology
- Clinical Biochemistry
- Biological Psychiatry
- Behavioral Neuroscience