RESUMEN
In experiments on mice, the effect of cyclic analogue of enkephalin (CAE) on the processes of learning and memory was studied in control animals and in animals with changed functional state of monoaminergic brain systems. Administration of the peptide to intact animals significantly accelerated the acquisition of conditioned reflexes of two-way avoidance and did not significantly affect the retention of these reflexes and their subsequent reproduction. Retention and reproduction of conditioned reflexes elaborated in one combination, was disturbed. Administration of iprazid did not eliminate the "accelerating effect" of CAE on the formation of conditioned reflexes of the two-way avoidance but sharply disturbed their retention. In such conditions, the amnesing iprazid effect increased still more. Besides, under CAE effect, the activity of acetylcholinesterase in the motor and especially in the visual cortex of the mice increased. The obtained data testify to an important role of the monoaminergic and cholinergic brain mechanisms in realization of CAE effects on the processes of learning and memory.
Asunto(s)
Reacción de Prevención/efectos de los fármacos , Condicionamiento Clásico/efectos de los fármacos , Encefalinas/farmacología , Memoria/efectos de los fármacos , Retención en Psicología/efectos de los fármacos , Acetilcolinesterasa/metabolismo , Animales , Aminas Biogénicas/fisiología , Fibras Colinérgicas/efectos de los fármacos , Masculino , Ratones , Corteza Motora/enzimología , Transmisión Sináptica/efectos de los fármacos , Corteza Visual/enzimologíaRESUMEN
On immobile rats it has been shown that subcuteneous injection of two different neuropeptides causes different distribution of activating, inhibiting and areactive cells resulting from microionoforetically administrated acetylcholine and noradrenaline without altering the mean frequency of the background unit activity sensorimotor cortical neurons. At the same time the alteration in the pattern of neurons impulse activity has been revealed, which acquires the character of packet activity with a specific packet length of 2-3, 4-6, 7-10 impulses. Depending on the injected neuropeptide reliable but almost contrary effects of the packet activity alterations have been observed. These effects have been suggested to result from the alteration of the chemoreactive properties of the neuron membranes and the corresponding reorganisations of interneuron attitudes.
Asunto(s)
Arginina Vasopresina/análogos & derivados , Células Quimiorreceptoras/efectos de los fármacos , Encefalinas/farmacología , Corteza Motora/efectos de los fármacos , Neuronas/efectos de los fármacos , Acetilcolina/farmacología , Animales , Arginina Vasopresina/farmacología , Interacciones Farmacológicas , Potenciales Evocados/efectos de los fármacos , Iontoforesis , Norepinefrina/farmacología , RatasRESUMEN
A mathematical model is presented which quantitatively describes the value of secreted mediator to each subsequent impulse in the series of presynaptic impulses. The model is constructed with the account taken of the role of presynaptic adrenoreceptors regulating noradrenaline secretion. An analysis of the model shows that the observed decrease and further stabilization of presynaptic responses in the series of presynaptic impulses observed in neurophysiological experiments can be connected with the work of alpha- and beta-autoadrenoreceptors. The increase of impulsation frequency affects the sensitivity of these receptors, which brings about an increase of concentration of secreted to each subsequent impulse mediator in the synaptic slit in the series of presynaptic impulses and stabilization of secretion at a higher level.
Asunto(s)
Norepinefrina/metabolismo , Receptores Adrenérgicos/fisiología , Receptores de Neurotransmisores/fisiología , Animales , Estimulación Eléctrica , Técnicas In Vitro , Modelos BiológicosRESUMEN
Subcutaneous injection of 10 micrograms desglycilargininvasopressin (DG-AVP) does not alter the mean frequency of background unit activity of sensorimotor cortical neurons. However, the pattern of impulse activity is essentially changed. At the same time the reactions of sensorimotor cortical neurons to microiontophoretic administration of acetylcholine and noradrenaline experience definite changes. It is suggested that the DG-AVP-induced changes in chemoreactive properties of neurons underlie the effect of this peptide on the learning and memory.
Asunto(s)
Acetilcolina/farmacología , Arginina Vasopresina/análogos & derivados , Norepinefrina/farmacología , Corteza Somatosensorial/efectos de los fármacos , Acetilcolina/administración & dosificación , Animales , Arginina Vasopresina/administración & dosificación , Arginina Vasopresina/farmacología , Inyecciones Subcutáneas , Iontoforesis , Norepinefrina/administración & dosificación , Ratas , Corteza Somatosensorial/fisiologíaRESUMEN
A mathematical model quantitatively describing the value of secreted mediator per each successive impulse in the series of presynaptic impulses is presented. The model is plotted with the account taken of the role of presynaptic adrenoreceptors regulating noradrenaline secretion. It has been shown that a decrease observed in neurophysiological experiments and further stabilization of postsynaptic responses in the series of presynaptic impulses of given frequency are not connected with a decreased content of noradrenaline in nerve endings, but may be connected with the work of presynaptic alpha and beta adrenoreceptors.