Ultrastructure of synapses in the cerebellar cortex after long-term activation of climbing fibres.
Adult male rats were treated for 24 or 48 h with harmaline which selectively activates neurones in the inferior olivary nucleus which give rise to climbing fibres projecting to the cerebellar vermis. Electrophysiological studies have shown that harmaline-induced climbing fibre activity completely blocks the responses of the Purkinje cell to parallel fibre input. Morphometric analysis of the ultrastructure of climbing and parallel fibre synapses revealed no significant differences in morphology between vermis (experimental) and hemisphere (control). These findings indicate that the decreased responsiveness of Purkinje cells to parallel fibre inputs induced by increased climbing fibre activity over 24 or 48 h is not accompanied by any observable structural changes in the cerebellar cortex.
Hawdon
G
G
Department of Physiology, Monash University, Clayton, Vic., Australia.
Rees
S
S
Rawson
J A
JA
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002525:Cerebellar Cortex / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D006246:Harmaline / Q000494:pharmacology; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
D006246:Harmaline