EFFECT OF CHRONIC PRETREATMENT WITH THE SIGMA-LIGAND JO-1784 ON CRF-INDUCED CHANGES IN BEHAVIOR NEUROTRANSMITTER AND IMMUNOLOGICAL FUNCTIONIN THE RAT

The effects of the chronic administration of the sigma ligand JO 1784 (igmesine) CRF-induced changes in some behavioural, immune, endocrine and neurotransmitter parameters were studied. In the elevated plus maz e, CRF (1.0 mu g i.c.v. daily x 5 days) induced a reduction in the num ber of entries and time spent on the open arms was significantly atten uated by the sigma ligand JO 1784 (3 mg/kg x 21 days) treatment. In th e 'open field' apparatus, the CRF-induced increase in the locomotor ac tivity was also reduced by JO 1784 administration. JO 1784 treatment d id not alter the concentration of the biogenic amine transmitters in t he hypothalamus, nor reverse the increase in the turnover of serotonin and dopamine caused by CRF. JO 1784 treatment also failed to reverse a CRF-induced increase in the serum corticosterone, but it did reverse the reduction in phytohaemagglutinin and concanavalin A-induced lymph ocyte proliferation caused by CRF but nut the changes in the lymphocyt e and neutrophil numbers caused by the peptide, These results demonstr ate that JO 1784 has some antistress properties in CRF-treated rats.