Effects of inflammatory pain, short stress of maternal isolation and combination of these impacts in 1-day-old and repeatedly 2-day-old rat pups (neonatal period of development) on the indices of generalized pain and the inflammatory pain response were studied on the rats during the adulthood. To study the involvement of 5-HT1A receptors in the long-term impact of neonatal effects on pain sensitivity we used a chronic injection of 5-HT1A receptor agonist buspirone during the prepuberal period of rats which as newborn experienced similar impacts (control, injection of saline). It was found that in adult rats in which inflammatory pain and stress of maternal isolation during the first two days of life caused changes in pain sensitivity, buspirone normalized the indices of basic pain in the hot plate test and the pain response in the formalin test; the combination of these impacts did not cause any changes in the pain sensitivity, and the effect of buspirone did not appear. Thus, effects of buspirone found in this study suggest that 5-HT1A receptors are involved in the long-term influence of the studied adverse neonatal impacts on the reactivity of the nociceptive system.