Endogenous opioids and fever: a hypothesis.

The explosion of knowledge set off by the characterization of endorphins and their receptors has created opportunities for new perspectives on a variety of phenomena. This brief essay examines one such phenomenon--the human febrile response--and proposes an alteration of the current model of the neuroendocrine circuitry controlling body temperature. Using behavioral thermoregulation as a starting point, we shall touch upon implications of this model for describing other forms of goal-directed motor activity.