Substance P-induced increase in vascular permeability in the rat trachea does not depend on neutrophils or other components of circulating blood.
An intravascular injection of substance P is known to increase vascular permeability in the rat trachea. Electrical stimulation of the cervical vagus nerve produces a similar response, presumably by releasing substance P or other tachykinins from sensory nerve endings. In the present study, we sought to determine whether the increase in vascular permeability induced by intravascular substance P or by vagal stimulation requires the presence of neutrophils or other components of circulating blood. To eliminate circulating blood, we perfused into the aorta of anesthetized rats an oxygenated Krebs-Henseleit solution containing albumin and monastral blue, a colloidal pigment that does not cross normal tracheal blood vessels. We then injected substance P intravascularly or electrically stimulated the right cervical vagus nerve. Increases in vascular permeability were quantified by using a microspectophotometer to measure the amount of extravasated monastral blue in tracheal whole-mounts. We found that the elimination of neutrophils and other components of circulating blood did not prevent the increase in tracheal vascular permeability induced by intravascular substance P or by vagal stimulation.
Bethel
R A
RA
Cardiovascular Research Institute, University of California, San Francisco.
Brokaw
J J
JJ
Evans
T W
TW
Nadel
J A
JA
McDonald
D M
DM
D000818:Animals; D001773:Blood Cells / Q000502:physiology; D002199:Capillary Permeability / Q000187:drug effects*; D004558:Electric Stimulation; D005260:Female; D009504:Neutrophils / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000494:pharmacology*; D014132:Trachea / Q000098:blood supply* / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology
D013373:Substance P