Inhibition of adjuvant arthritis by salbutamol and aminophylline

Salbutamol (3 mg/kg) and aminophylline (75 mg/kg) were administered s.c. to rats separately or in combination after intradermal injection of adjuvant into the left hind paw. The paw volume was measured plethysmographically; tissue cyclic AMP content was determined by a protein binding assay following whole body microwave irradiation. The combination of salbutamol and aminophylline given daily significantly inhibited the swelling response in both the adjuvant-injected and the non-injected paws. This drug combination significantly increased the cyclic AMP levels in inflamed tissue of the adjuvant-injected hind paw and in lymphoid tissue such as the spleen and thymus. The combined treatment seems to have immunosuppressive as well as anti-inflammatory effects on adjuvant-induced arthritis.