guanosine-diphosphate and 3-4-dihydroxyphenylglycol

Here, we examined long-term synaptic plasticity in the avian auditory midbrain, a region involved in experience-dependent learning. We found that coactivation of N-methyl-D-aspartate receptors (NMDAR) and type 1 cannabinoid receptors (CB1R) induces long-term depression (LTD) at the synapse between the central shell and the external portion of the inferior colliculus of the chicken. Although endocannabinoids are commonly thought of as presynaptic modulators, recent reports have suggested that they can also modulate the postsynaptic site. In the avian midbrain, we found that LTD is mediated by both presynaptic and postsynaptic changes. The presynaptic mechanism consists of a decrease in neurotransmitter release, whereas a depression of NMDAR-mediated current takes place on the postsynaptic side. Both the presynaptic and the postsynaptic effects depend on CB1R activation. The reduction of postsynaptic NMDAR currents represents a novel role of endocannabinoids in synaptic modulation.

Topics: Animals; Biophysics; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cannabinoid Receptor Modulators; Chelating Agents; Chick Embryo; Egtazic Acid; Electric Stimulation; Endocannabinoids; Enzyme Inhibitors; Excitatory Amino Acid Agents; Guanosine Diphosphate; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Long-Term Synaptic Depression; Mesencephalon; Methoxyhydroxyphenylglycol; Neurons; Patch-Clamp Techniques; Peptide Fragments; Pertussis Toxin; Piperidines; Presynaptic Terminals; Pyrazoles; Synapses; Thionucleotides