Changes of the central neuronal systems are important manifestation of many neurological disturbances, mainly of the old age. The aim of the study was to examine reactivity of D1,D3, central dopamine (DA) and serotonin 5-HT2C, receptors during ontogenic development in rats. For this purpose we have used specific receptor agonist and behavioral procedures such as oral activity and yawning. Male Wistar rats were challenged intraperitoneally with D1, central DA agonist - SKF 38393: 0.03 -1.0; D2,/D3, central DA agonist - quinpirole: 0.0125 - 0.2 or 5-HT2C, agonist - mCPP (m-chlorphenyl-piperazine): 0.3-6.0 mg/kg. This procedure was repeated every month since the 1st till the 16-18th month of postnatal life. Number of oral movements or yawns was recorded during one hour observation period. On the basis of these results we can conclude that during the aging process in rats, reactivity of D1, central DA and 5-HT2C, receptors is decreased. D3, central dopamine receptor reactivity is increased in the second month of life, then decreased as aging progress.

Keywords: dopamine receptors, serotonin receptors, SKF 38393, aging process