Neurochemical sensitization associated with systemic administration of tumor necrosis factor-alpha: adjuvant action in combination with bovine serum albumin.

Tumor necrosis factor-alpha (TNF-alpha) provokes a time-dependent sensitization of brain monoamine activity, plasma corticosterone activity and sickness behavior, the latter being reminiscent of septic or anaphylactic shock. In this investigation, bovine serum albumin (BSA) elicited similar corticosterone and sickness profiles, whereas the monoamine changes were not observed. The sensitization elicited by mTNF-alpha plus BSA was markedly greater than that elicited by BSA alone. Carrier-free TNF-alpha promoted the sensitization of brain monoamine activity, but not sickness or corticosterone. It is suggested that mTNF-alpha acts as an adjuvant to the anaphylactic actions elicited by BSA, but may provoke a sensitization of monoamine activity which is time-dependent and varies across brain regions.