This article presents current views on the cellular and molecular bases of the central mechanisms of neuroimmune interactions, along with data on the effects of destabilizing factors (painful electrical stimulation, cold, psychoemotional stress) on the functions of neurons and immunocompetent cells. It is important to emphasize that stress is associated with changes in ligand-receptor interactions on the membranes of lymphoid cells which respond to the interleukin-1 regulatory signal; these changes consist either of enhanced responses to this regulatory signal (in mild stress situations) or sharp decreases in responses (on exposure to strongly stressful factors). Special attention is paid to the role of the orexinergic system in the mechanisms mediating the brain’s responses to administration of antigens and exposure to stressors. We consider possible means of correcting the imbalance in the functional interaction between the nervous and immune systems occurring as a result of various destabilizing factors.