Effects of Intranasal Challenge with Histamine, Bradykinin and Prostaglandin on Middle Car Pressure and Blood Flow in Cynomolgus Monkeys

Abstract

Preyious studies documented a significant increase in middle Car pressure following intranasal challenges with asCaris antigen or histamine in sensitized cynomolgus monkeys. To confirm that effects and inyestigate the mechanism, 4 monkeys were intranasally challenged at separate sessions with histamine (1O mg). bradykinin (1, 10 mg) and prostaglandin D2 (PgD2. 0.5. 1.0 mg) and followed for 90 min. Before and after challenge, middle Car pressure, mucosal blood How. hCart rate, blood pressure, body temperature and the partial pressures of O₂ and CO₂ in the yenous blood were measured. The results showed that while bradykinin challenge had no effect on these measures. PgD2 proyoked increased middle Car pressure, and histamine resulted in a biphasic pattern of increasing pressures followed by decreasing pressures. The pattern of change in middle Car pressure after histamine challenge was explicable by a mechanism inyolying transmucosal gas exchange, while that for PgD2 was related to increased mucosal inflammation. These results document the deyelopment of positiye middle Car pressures during proyoked nasal inflammation and may haye relevance to similar obseryations in the clinical setting.

Key Words:

• nasal challenge
• middle Car pressure
• blood flow
• laser-Doppler
• gas exchange