In this randomised, cross-over, controlled study a total of 84 subjects will be included: 12 healthy non-smoking volunteers; 12 current smokers; 30 patients with mild steroid-naïve asthma, and 30 patients with mild-moderate COPD.

Each subject will have 1 screening visit (if necessary) and 2 study visits. At visits 2 and 3 the effect of ATP or AMP challenge given in a random order will be tested.

Accepts Healthy Volunteers

Inclusion Criteria:

1. Healthy non-smokers (n=12)

   • Normal spirometry
   • FEV1 reversibility of <15% after inhaled beta2-agonists*

2. 0: At risk (current smokers) (n=12)*

   • Normal spirometry, chronic symptoms (cough, sputum production)
   • FEV1 reversibility of <15% after inhaled beta2-agonists* * = Global Strategy for the Diagnosis, Management, and Prevention of COPD)

3. Mild steroid-naïve asthma (n=30)

   - FEV1 more than or equal to 80%

4. Mild-moderate COPD (n=30) - FEV1 50-80 % FEV1

Exclusion Criteria:

• Pregnancy, breast-feeding or planned pregnancy during the study. Fertile women not using acceptable contraceptive measures, as judged by the investigator • Upper respiratory infection within the last 4 weeks • Subjects who have received research medication within the previous one month • Subjects unable to give informed consent • Any psychiatric condition rendering the patient unable to understand the nature, scope and possible consequences of the study.