Modifications of plastic properties and metaplasticity of glutamatergic synapses in the rat cortex and hippocampus under conditions of reserpine-induced behavioral depression

• Published in: Neurophysiology (New York) Vol. 39; no. 3; pp. 184 - 190
• Main Authors: Abramets, I. I., Evdokimov, D. V., Talalaenko, A. N.
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.05.2007
• Subjects: Anatomy & physiology; Animal behavior; Biochemistry; Brain research; Mental depression; Neurology; Neurons; Neurotransmitters; Rodents
• ISSN: 0090-2977; 1573-9007
• DOI: 10.1007/s11062-007-0025-6

Intraperitoneal injection of 1 mg/kg reserpine into rats caused the development of behavioral depression that was especially clearly pronounced 24 h after injection. Under such conditions, induction of long-term potentiation of synaptic transmission was suppressed, the development of long-term depression in glutamatergic synapses of pyramidal neurons of the hippocampal CA1 area and layers II/III of the parietal cortex was facilitated, and metaplasticity threshold ( M ) was shifted to the right. Such modifications of plasticity and metaplasticity of glutamatergic synapses were determined by changes in the functional state of postsynaptic NMDA receptors, which was confirmed by a decrease in the duration of NMDA component of field EPSPs generated in the studied neurons and by an increase in the sensitivity of this component to the action of a nonselective blocker of NMDA receptors, ketamine. Simultaneously, the sensitivity to zinc and haloperidol, which are selective with respect to NMDA receptors with the subunit composition NR1/NR2B, decreased. It is hypothesized that, under conditions of depression, either replacement of a part of NR2B subunits in the structure of NMDA receptors by NR2A subunits or biochemical inactivation of NMDA receptors containing NR2B subunit, as well as a decrease in the clearance of transmitter in glutamatergic synapses, occur; these events determine the impairment of plastic properties of the latter contacts. [PUBLICATION ABSTRACT]