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Effect of PAF on selected smooth muscle preparations
S Jancar1, P Thériault, P Sirois
1Dépt. Pharmacologie, Faculté de Médecine, Université de Sherbrooke, Canada.
Research Communications in Chemical Pathology and Pharmacology
|January 1, 1989
Summary
Platelet-activating factor (PAF) demonstrated potent myotropic activity on smooth muscle tissues, inducing strong contractions. Tachyphylaxis was a common observation, indicating a desensitization to repeated PAF exposure.
Area of Science:
- Pharmacology
- Smooth Muscle Physiology
Background:
- Platelet-activating factor (PAF) is a potent lipid mediator involved in various physiological and pathological processes.
- Smooth muscle preparations are crucial for studying drug effects and physiological responses.
Purpose of the Study:
- To investigate the myotropic (contractile) activity of PAF on smooth muscle.
- To compare PAF's effects with other known myotropic and spasmolytic agents.
Main Methods:
- Studied myotropic activity of PAF on rat and guinea-pig smooth muscle preparations.
- Compared responses to histamine, acetylcholine, norepinephrine, leukotriene D4 (LTD4), prostaglandin E2 (PGE2), and F2 alpha (PGF2α).
Main Results:
- Nanogram quantities of PAF induced significant contractile responses in smooth muscle.
- Tachyphylaxis was a common characteristic of PAF-induced contractions.
- Responses to PAF were typically slow in onset and sustained.
- Leukotriene D4 and prostaglandin E2 also caused contraction, except in lung tissues where PGE2 induced relaxation.
Conclusions:
- PAF exhibits potent myotropic activity on various smooth muscle tissues.
- Tachyphylaxis is a key feature of PAF's action on smooth muscle.
- PAF's contractile effects differ from other mediators, particularly in lung tissue responses to PGE2.