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Effects of platelet-activating factor on rat airways
1Department of Applied Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
Japanese Journal of Pharmacology
|September 1, 1988
Summary
Platelet-activating factor (PAF) is a potent bronchoconstrictor in rats, causing airway narrowing and decreased blood pressure. Repeated PAF exposure leads to tachyphylaxis in airway constriction but not in blood pressure effects.
Area of Science:
- Pharmacology
- Respiratory Physiology
- Inflammation Research
Background:
- Platelet-activating factor (PAF) is a lipid mediator implicated in inflammatory responses.
- Its specific effects on airway smooth muscle and interactions with other mediators require detailed investigation.
Purpose of the Study:
- To investigate the effects of inhaled platelet-activating factor (PAF) on rat airways.
- To compare the bronchoconstrictor potency of PAF with acetylcholine (ACh) and histamine.
- To examine the systemic effects and tachyphylaxis of PAF in rats.
Main Methods:
- Male Wistar rats were exposed to inhaled PAF via tracheal cannula.
- Bronchomotor responses were measured using the Konzett-Rössler method.
- Systemic blood pressure changes and tachyphylaxis were assessed following repeated PAF inhalations.
Main Results:
- Inhaled PAF induced dose-dependent bronchoconstriction, significantly more potent than ACh.
- PAF caused a dose-dependent decrease in systemic blood pressure.
- Repeated PAF exposure resulted in tachyphylaxis of bronchoconstriction but not hypotension.
- No potentiation of ACh or histamine responses was observed with combined PAF inhalation.
Conclusions:
- Platelet-activating factor (PAF) is a potent bronchoconstrictor in the rat airway model.
- PAF elicits significant hypotensive effects in rats.
- Tachyphylaxis develops specifically to the bronchoconstrictor action of PAF.
- PAF does not interact to potentiate the acute bronchoconstrictor effects of ACh or histamine.