INTRACEREBRAL ADMINISTRATION OF MYCOPLASMA-FERMENTANS PRODUCES SICKNESS BEHAVIOR - ROLE OF PROSTAGLANDINS

Mycoplasmas are small microorganisms, which cause various diseases in animals and in humans, activate the immune system, and induce the rele ase of various cytokines. Some of the effects of mycoplasmas are media ted by the CNS. Moreover, Mycoplasma fermentans (MF) has recently been found in the brain, as well as other tissues of some AIDS patients, w ho usually display severe neurobehavioral disturbances. The present st udy was designed to examine the behavioral effects of central administ ration of MF, and the role of prostaglandins in mediating these effect s. In one set of experiments, rats were injected intracerebroventricul arly (i.c.v.) with either saline or a dose of MF (5.1-36 mu g per rat) , and several behavioral parameters were measured. In addition, body t emperature and locomotor activity were continuously monitored by a bio telemetric system. MF induced a significant elevation in body temperat ure and suppression of motor activity levels. MF also significantly re duced the time spent in social exploration, decreased locomotor and ex ploratory activity in the open field test, suppressed the consumption of food and saccharine solution, and reduced body weight. In a second set of experiments, i.c.v. administration of MF (7.2 mu g) was found t o produce a significant increase in the production of prostaglandin E( 2) (PGE(2)) in hypothalamic, hippocampal, and cortical tissues. This e ffect was blocked by indomethacin, a prostaglandin synthesis inhibitor . Indomethacin also attenuated the effects of MF on body temperature, motor activity and body weight, suggesting the involvement of prostagl andins in mediating some of the effects of MF. Together, these finding s suggest that the presence of MF in the brain may be responsible for some of the neurobehavioral abnormalities in HIV-infected patients.