Morphological and pharmacological evidence for the existence of brain regulatory circuits in the immune response.

Muramyl dipeptide (MDP) has a variety of biological effects including the effect on CNS, such a promotion of sleep, fever, analgesic effect or some behavioural changes and of course a very potent effect on immune system. The latter effect is at least partly mediated through the structure in CNS. With the small electrolytic lesions which were placed in brain from the spinal cord through the brain stem up to the cerebral cortex we have identified a number of structures such as medial frontal cortex (area Cg1-Cg3), subnucleus basomedialis and centralis of amygdala, subnucleus medialis and dorsolateralis of nucleus parabrachialis, lateral part of reticular formation (monoaminergic groups A1-7) and the part of the reticular formation (serotonergic groups B6-B8) which are evidently involved in the immunomodulatory and immunoadjuvant effect of muramyl dipeptide. The results of experiments also suggest that the interaction between neuroendocrine and immune systems might take place on the level of some of above mentioned anatomical structures.