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Anatomic basis for species differences in peripheral lung strip contraction to PAF
M Halonen1, A M Dunn, J D Palmer
1Department of Pharmacology, University of Arizona Health Sciences Center, Tucson 85724.
The American Journal of Physiology
|August 1, 1990
Summary
Platelet-activating factor (PAF) strongly contracts guinea pig lung tissue due to pleural smooth muscle. This muscle is absent in rabbits, explaining PAF
Area of Science:
- Pulmonary Physiology
- Smooth Muscle Biology
- Pharmacology
Background:
- Platelet-activating factor (PAF) is a potent contractile agent in guinea pig peripheral lung strips.
- PAF has no effect on rabbit peripheral lung strips, suggesting species-specific mechanisms.
Purpose of the Study:
- To investigate the cellular basis for PAF-induced contraction in guinea pig lung.
- To identify the specific tissue responsible for PAF responsiveness.
Main Methods:
- Histological examination of guinea pig and rabbit lung strips.
- Excision of the pleural surface from guinea pig lung strips.
- Assessment of contractile responses to PAF, histamine, and leukotriene D4 (LTD4) in intact and de-pleuralized tissues.
Main Results:
- Guinea pig peripheral lung strips possess a smooth muscle layer in the visceral pleura, absent in rabbits.
- Removal of the pleural surface abolished PAF-induced contraction in guinea pig lung strips.
- The removed pleural strips contracted to PAF, while histamine and LTD4 contracted other lung elements.
Conclusions:
- Pleural smooth muscle is the primary contractile element mediating PAF responses in guinea pig peripheral lung.
- Histamine and LTD4 act on additional contractile elements beyond the pleural smooth muscle.