Neuronal mechanisms contribute to corticotropin-releasing factor-induced anti-oedema effect in the rat hind paw

Abstract

The present study is designed to elucidate the involvement of neuronal mechanisms in corticotropin-releasing factor (CRF)-induced anti-oedema effects. Oedema was induced in the rat hind paw by subcutaneous injection of 3nmol of serotonin (5-HT). A single dose of CRF (9.4, 37.5 or 75pmol) was given either ipsilaterally or contralaterally 30min before 5-HT injection and oedema formation was subsequently measured every 30min for 5.5h. Compared to saline pre-treatment CRF (37.5pmol) reduced oedema formation for 3.5h when given ipsilaterally, and at 1.5h (9.33, 37.5 and 75pmol) when injected contralaterally. Administration of CRF along with CRF receptor antagonist, alpha-helical CRF, abolished the anti-oedema effects of CRF. Sciatic nerve ligation on the injected side attenuated the ipsilateral CRF-induced anti-oedema effect when compared with saline pre-treatment and sham-operated rats. Ipsilateral pre-treatment with 37.5pmol of CRF caused a reduction in hind paw temperature compared to treatment with saline. Results of the present study indicate that the nervous system contributes to CRF effects in 5-HT-induced oedema formation.