Plastic reorganization of hippocampal synapses resulted from pharmacological blockade of type 1 cannabinoid receptors

Abstract

Endogenous cannabinoid system plays an important physiologicalrole in brain functioning, being related to regulation of neuromediatorprocesses and mechanisms of neuroplasticity.Cannabinoid receptors of type 1 (CB1) represent one of the keyelements of this system and convenient object for various experimentaleffects. We showed plastic reorganization of synapses inhippocampal CA1 stratum radiatum in vitro resulted from pharmacologicalblockade of CB1. The ultrastructural features of thisreorganization are the formation of numerous perforated contactswith elongated synaptic membranes of modified configuration,spatial synaptic rearrangement, and the appearance ofatypical synaptic connections. The obtained results suggest thatinvolvement of CB1 in modulation of synaptic transmission isone of the mechanisms which ensure the stable morphofunctionalstate of synapse and promote its integrity in disturbancesof neurotransmission regulation.

Keywords

• hippocampus
• tissue culture
• cannabinoid receptors
• synaptic regulation
• plasticity
• glutamate
• neurotoxicity