[Aggressive behavior and radiosensitivity in rats']

This paper aims to present the study of rats' individual radiosensitivity dependence on their individual aggressiveness. On total irradiation in sublethal doses (1.0, 1.5 and 3.5 Gy) and in doses close to LD50/30 (6, 7 and 8 Gy) there was investigated comparative radiosensitivity of non-aggressive and aggressive rats of Wistar line, as well as that of non-aggressive individuals during provoked aggressiveness by means of blocking serotonin synthesis with intraperitoneal (i/p) injection of 400 mg/kg of parachlorphenylalanine (pCPA). Muricidity served as a criterion for aggressiveness and as a criterion of radiosensitivity--cumulative function of survival, the changes of behavior in "Open feald", serotonine and catecholamine content in various brain structures and the dose dependence on the radiation modification of muricidity. It has been found that after 1 Gy total X-irradiation the rats do not lose aggressiveness. Nevertheless the ethalogical parameters change in considerable degree. In the doses of 1.5 and 3.5 Gy muricidity is eluminated in 15-18 and 5-9 days, correspondingly. I/p injection of pCPA after the elimination of aggressiveness provokes transient muricidity in the same terms and duration as it is in case of non-aggressive rats. The elimination of muricidity is associated with changes in content and distribution of biogenic amines in various structures of brain, as well as with reduction of locomotor and reference-research activity, on the one hand and with an increase of emotionality and stereotype activity, on the other hand. After X-irradiation in 6, 7 and 8 Gy the regression coefficients of the dependence of functions type of survival on irradiation dose in aggressive rats is significantly reliable both in comparison with non-aggressive rats and animals with provoked aggressiveness. The change of mortality-rate per unit of changing irradiation dose not depend on blocking of serotonin synthesis, which deficit is one of the distinct determinant of aggressiveness, on the one hand, and higher radiosensitivity, on the other hand. The obtained data allow to suppose that elimination of muricidity after the irradiation of rats in the sublethal doses is conditioned not only by the consequenses of radiation damage of neurobiological structures responsible for the organization of aggressive behavior but the activation of serotonergic system in the process of restitution after radiation trauma. On the other hand, higher radiosensitivity of aggressive rats compared with non-aggressive ones is connected with low serotonin content, thiols and some other biologically active substances which are endogenous radioprotectors determining individual radioresistance.