Efflux of cyclic AMP,prostaglandin E2 and F2 and thromboxane B2 in leg lymph of rabbits after scalding injury

Leg lymph was collected from pentobarbital anaesthetized rabbits before and after scalding injury of the paw (75°C for 20 s), and the contents of cyclic AMP (cAMP), prostaglandin E₂ (PGE₂) and PGF_2α and thromboxane B₂ (TXB₂) in lymph were determined. After injury lymph flow increased about four times. The maximal rate of flow was found between 30 and 60 min after scalding. The efflux of cAMP and immunoreactive iPGE₂, iPGF_2α and iTXB₂ also increased. The maximum values were detected at approximately 0–30, 30–60, 30–60 and 180–240 min, respectively, after the injury. The output of cAMP, iPGE₂ and iPGF_2α and iTXB₂ in lymph of the contralateral non-scalded paw remained low throughout the experiments. When rabbits were injected with indomethacin (2.5 mg/kg) or diclofenac sodium (2.5 mg/kg) immediately after the scalding injury, the efflux of cAMP, iPGE₂ and iPGF_2α were low. Lymph flow was markedly reduced after treatment with diclofenac sodium; treatment with indomethacin did not significantly affect lymph flow. The results suggest a prostaglandin-dependent formation of cAMP following scalding injury which may be related to the initial responses to scalding.