Plasma extravasation in the rat trachea induced by cold air is mediated by tachykinin release from sensory nerves.
Cold air was delivered to anesthetized, artificially ventilated, pathogen-free F344 rats via a tracheal cannula. Inhalation of cold air increased Evans blue dye extravasation in the trachea in a time-dependent (1 to 10 min) manner. Plasma extravasation increased after 3 min exposure to cold air and reached a maximum after 10 min exposure. The neutral endopeptidase inhibitor, phosphoramidon (2.5 mg/kg, intravenously), increased by 84% the plasma extravasation induced by inhalation of cold air for 1 min. The plasma extravasation evoked by 5 min exposure to cold air was abolished by the NK1 tachykinin receptor antagonist, CP-99,994 (4 mg/kg, intravenously); was reduced 30% by the B2 bradykinin receptor antagonist, HOE140 (0.1 mumol/kg, intravenously); and was not affected by H1 (pyrilamine, 10 mg/kg, intraperitoneally) or H2 (cimetidine, 10 mg/kg, intraperitoneally) histamine receptor antagonists or the cyclooxygenase inhibitor indomethacin (5 mg/kg, intravenously). In rats infected with Sendai virus, plasma extravasation evoked by inhalation of cold air was greater than in pathogen-free rats. Pretreatment with CP-99,994 (4 mg/kg, intravenously) inhibited completely the plasma extravasation induced by cold air in virus-infected rats. These findings indicate that cold air increases plasma extravasation in the rat trachea by a neurogenic mechanism that involves the release of tachykinins from sensory nerves. Kinin release may also play a role in this neurogenic inflammatory response.
Yoshihara
S
S
Cardiovascular Research Institute, University of California San Francisco 94143-0130.
Chan
B
B
Yamawaki
I
I
Geppetti
P
P
Ricciardolo
F L
FL
Massion
P P
PP
Nadel
J A
JA
D000388:Air; D000818:Animals; D003080:Cold Temperature; D005070:Evans Blue / Q000493:pharmacokinetics; D005119:Extravasation of Diagnostic and Therapeutic Materials; D015287:Neurokinin B / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism*; D010222:Parainfluenza Virus 1, Human; D051381:Rats; D011916:Rats, Inbred F344; D012121:Respiration, Artificial; D014132:Trachea / Q000294:innervation*; D014136:Tracheitis / Q000378:metabolism*; D014777:Virus Diseases / Q000378:metabolism*
D005070:Evans Blue; D015287:Neurokinin B