Expression and biophysical properties of Nav1.9 ion channels in pyramidal neurons of the prefrontal cortex in individuals of different ages

The aim of the project is to study the expression and characterization of the biophysical properties of Na + ion channels of the NaV1.9 type and to compare these properties in layer V pyramidal neurons of the prefrontal cortex (PFC) of rats of different ages. It is believed that the proper functioning of the PFC neurons is responsible for the behavior of the body and the changes in the body's behavior related to age. Impaired PFC activity is the cause of the majority of age-related neuropsychiatric diseases, which affect 34% of the citizens of the European Union. The physiological and pathophysiological activity of PFC neurons depends, inter alia, on the expression and biophysical properties of the ion channels present in these neurons. We have recently shown that TTX-independent ion channels of the NaV1.9 type can play an important role in the regulation of PFC neurons activity. Electrophysiological studies will be performed on layer V pyramidal neurons of the medial PFC, located in sections isolated from male young rats (18-22 days), maturation (38-42 days), adults (60-65 days) and possibly old ( 20 months). The frontal lobes will be cut into sections. Pyramidal neurons will be identified in infrared and DIC light. Records of single Nav1.9 channel ion currents will be carried out from the cell body of neurons using the method of stabilizing the potential on the surface of the patch. Will be determined, inter alia the probability of openings, the average time of openings, amplitude, activation, inactivation depending on the potential and time of the tested channel ion currents. The analysis of the results will be performed using Clampfit 9.0 and standard statistical tests. Neurons located in sections of young (18-22 days old), adolescent (38-42 days old), adult (58-62 days old) and old (20 month old) rats obtained from fixed brains will be labeled with Map2. Expression of Nav1.9 ion channels will be examined by immunofluorescence using a confocal microscope in pyramidal neurons identified by shape (triangular shape, presence of apical dendrite, presence of basal dendrites). The biophysical properties and the expression of Nav1.9 ion channels in rats of different ages will be compared. The excitation threshold for potential-dependent Na + ion channels of the NaV1.9 type is similar to the value of the resting membrane potential. Accordingly, reducing or increasing the likelihood of openings of these channels (caused by biologically active compounds, neurotransmitters) causes hyperpolarisation or depolarization of the cell membrane of neurons, respectively, and thus alters the excitability of the neurons. The resting membrane potential is depolarized in pyramidal neurons. These depolarizations increase the excitability of neurons, which is the functional basis of working memory. A disorder of these depolarizations occurs in epilepsy, schizophrenia, and in the natural or accelerated aging of the central nervous system. The cellular effector responsible for producing these depolarizations is not defined. The results obtained in our and other laboratories indicate that the activation of the Nav1.9 channel may be responsible for the depolarization of PFC pyramidal neurons. The aim of this project is to record Nav1.9 ion channel currents and define their biophysical properties in PFC layer V pyramid neurons of different ages. Identification and understanding the mechanisms of operation of Na + ion channels of the NaV1.9 type at the cellular level is the basis for understanding the mechanisms responsible for changes in the body's behavior during individual development and for the introduction of optimal therapy and rational construction of drugs improving and correcting dysfunction of the activity of pyramidal neurons in the prefrontal cortex.