Differential expression of posttetanic potentiation and retrograde signaling mediate target-dependent short-term synaptic plasticity.
Short-term synaptic plasticity influences how presynaptic spike patterns control the firing of postsynaptic targets. Here we investigated whether specific mechanisms of short-term plasticity are regulated in a target-dependent manner by comparing synapses made by cerebellar granule cell parallel fibers onto Golgi cells (PF-->GC synapse) and Purkinje cells (PF-->PC synapse). Both synapses exhibited similar facilitation, suggesting that any differential short-term plasticity does not reflect differences in the initial release probability. PF-->PC synapses were highly sensitive to stimulus bursts, which could result in either depression of subsequent responses, mediated by endocannabinoid-dependent retrograde signaling, or enhancement of responses through posttetanic potentiation (PTP). In contrast, stimulus bursts had remarkably little effect on the strength of PF-->GC synapses. Unlike PCs, GCs were unable to regulate their PF synapses by releasing endocannabinoids. Moreover, PTP was reduced at the PF-->GC synapse compared to the PF-->PC synapse. Thus, the target-dependence of PF synapses arises from the differential expression of both retrograde signaling and PTP.
Beierlein
Michael
M
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Fioravante
Diasynou
D
Regehr
Wade G
WG
D000818:Animals; D000831:Animals, Newborn; D002531:Cerebellum / Q000166:cytology; D004307:Dose-Response Relationship, Radiation; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000172:deficiency; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D010880:Piperidines / Q000494:pharmacology; D011336:Probability; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D013569:Synapses / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects
D004791:Enzyme Inhibitors; D009419:Nerve Tissue Proteins; D010880:Piperidines; D011720:Pyrazoles; C485550:Unc13c protein, mouse; C103505:AM 251