Mitochondria-Targeted Plastoquinone Antioxidant SkQR1 Has Positive Effect on Memory of Rats

A single intraperitoneal injection to rats of the mitochondria-targeted plastoquinone antioxidant SkQR1 at dose 1 µmol/kg significantly improved reproduction by the rats of the passive avoidance conditional reflex. In vitro experiments on hippocampal slices showed that a single intraperitoneal injection of SkQR1 24 h before the preparation of the slice significantly increases the synaptic transmission efficiency of the pyramidal neurons of the CA1 field. The findings indicate that SkQR1 has a positive effect on memory processes.

Characteristics of the actions of neurotensin on motor reactions in rats in response to positive and negative conditioned signals

This study addressed the effects of microinjections of neurotensin into the caudate nucleus and substantia nigra on the performance of motor reactions in response to positive and negative conditioned signals, as well as the post-effects of microinjections in subsequent experiments. Neurotensin had positive effects on the extinction of non-reinforced motor reactions. Neurotensin had no effect on the number of motor responses to the non-reinforced signal, though the number decreased in subsequent experiments. There was an increase in the latent period of responses as compared with controls. The effect of neurotensin at the level of the caudate nucleus was more marked than that at the level of the substantia nigra. Neurotensin microinjections had no marked effect on performance of conditioned responses to positive signals. The behavioral effects of neurotensin are associated with normalization of the interactions of the brain's monoaminergic systems. It is suggested that the positive actions of neurotensin on extinction of motor responses to negative signals result from the formation of a contextual conditioned emotional state in the animals, this facilitating optimization of conditioned reflex activity.

The effects of microinjection of neurotensin into the caudate nucleus of the rat brain on the performance and extinction of a conditioned motor reflex

The studies reported here demonstrate that microinjection of neurotensin into the caudate nucleus of the rat brain facilitated extinction of a conditioned motor reflex with reinforcement provided by drinking. Neurotensin had positive effects on the process of post-extinction inhibition in subsequent experiments. Neurotensin microinjections had no marked effect on the performance of the conditioned reflex, though it weakened the emotional tension of the animals in an "open field" test. It is concluded that the functional importance of neurotensin at the level of the caudate nucleus is associated less with the regulation of motor function than with optimizing the motivational-emotional state of the animal.