Antinociceptive activity of impentamine, a histamine congener, after CNS administration.

Abstract

The brain neuromodulator histamine induces antinociception when administered directly into the rodent CNS. However, several compounds derived from H2 and H3 antagonists also produce antinociception after central administration. Pharmacological studies have shown that a prototype of these agents, improgan, induces analgesia that is not mediated by actions on known histamine receptors. Presently, the antinociceptive properties of a compound that chemically resembles both improgan and histamine were investigated in rats. Intraventricular (i.v.t.) administration of impentamine (4-imidazolylpentylamine) induced reversible, near-maximal antinociception on the hot plate and tail flick tests (15 microg, 98 nmol). The dose-response function was extremely steep, however, since other doses showed either no effect or behavioral toxicity. On the tail flick test, impentamine antinociception was resistant to antagonism by blockers of H1, H2, or H3 receptors, similar to characteristics previously found for improgan. In contrast, histamine antinociception was highly attenuated by H1 and H2 antagonists. These findings suggest that: 1) the histamine congener impentamine may induce antinociception by a mechanism similar to that produced by improgan, and 2) additional histamine receptors may be discovered that are linked to pain-attenuating processes.

• Authors: L B Hough, J W Nalwalk, R Leurs, W M Menge, H Timmerman
• Journal: Life sciences (Life Sci) Vol. 64 Issue 5 Pg. PL79-86 ( 1999) ISSN: 0024-3205 [Print] Netherlands
• PMID: 10072195 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Analgesics
• Histamine Agonists
• Histamine Antagonists
• Imidazoles
• Receptors, Histamine H1
• impentamine
• Histamine

Topics

• Analgesics (administration & dosage, pharmacology)
• Animals
• Cerebral Ventricles (drug effects, physiology)
• Dose-Response Relationship, Drug
• Guinea Pigs
• Histamine (pharmacology)
• Histamine Agonists (pharmacology)
• Histamine Antagonists (administration & dosage, pharmacology)
• Hot Temperature
• Imidazoles (administration & dosage, pharmacology)
• In Vitro Techniques
• Injections, Intraventricular
• Jejunum (drug effects, physiology)
• Male
• Microinjections
• Muscle, Smooth (drug effects, physiology)
• Pain (physiopathology, prevention & control)
• Rats
• Rats, Sprague-Dawley
• Receptors, Histamine H1 (drug effects, physiology)