THE EFFECT OF PERIPHERAL INOSITOL INJECTION ON RAT MOTOR-ACTIVITY MODELS OF DEPRESSION

Myo-inositol is an important precursor in cellular second-messenger sy nthesis. It has been reported to be reduced in the cerebrospinal fluid of depressed patients and to reverse a specific effect of Li on rat b ehavior when given intracerebroventricularly (i.c.v.). However, myo-in ositol enters the brain poorly when given peripherally, and its effect s on normal rat brain have not been well studied. A series of experime nts examined the effect of intraperitoneal inositol in high doses on l ocomotor activity, on amphetamine-induced hyperactivity, on apomorphin e-induced stereotyped behavior, and on pilocarpine-induced behaviors i n rats. In addition, the behavioral effect of i.c.v. inositol was comp ared to that of a control stereoisomer in untreated and lithium-treate d rats. Few effects of peripheral myo-inositol were found in these mod els. However, peripheral inositol in high doses given to rats exhibiti ng Li-pilocarpine seizures showed that i.p. inositol could prevent the se behaviors, confirming that peripheral inositol may have antidepress ant potential in appropriate models.