Inhalation of cotton dust can cause the appearance of byssinosis symptoms which are characterized by shortness of breath, cough, wheezing and decreased forced expiratory volume (FEV). There exist a number of theories for explaining the aetiology of the disease. It has been postulated that histamine could be one of the most active agents which can cause bronchoconstriction produced by the cotton dust exposure.

In the present work a new intraperitoneal technique for exposure has been used to study the total content of lung amines and the activity of some lung enzymes. This technique provides an advantage over the bronchial route of exposure since the exact dust concentration to which the animal is exposed can be determined.

The results of the present study revealed that the intraperitoneal injection of aqueous extract of cotton dust induced in guinea pigs an increase in the lung tissue total content of histamine and serotonin. The increase was maximum after 4 weeks of exposure.

However, a decline in the amines concentration was found during the period between 4 and 7 weeks. On continuing the exposure for more than 7 weeks the total content of amines increased again.

No significant change in histidine decraboxylase-activity was found. However, the diamine oxidase-activity was found to be inversely proportional to the total content of amines throughout the exposure time.

These results provide evidence for the technique validity and the essential role of histamine and serotonin as causative agents in the appearance of byssinosis symptoms.