title: Synaptic ribbons of a mammalian pineal gland circadian changes.
mesh_terms: D000818:Animals; D002462:Cell Membrane; D002940:Circadian Rhythm; D003624:Darkness; D006168:Guinea Pigs / Q000033:anatomy & histology*; D008027:Light; D008297:Male; D008854:Microscopy, Electron; D010870:Pineal Gland / Q000166:cytology* / Q000378:metabolism; D013569:Synapses / Q000166:cytology* / Q000502:physiology; D013572:Synaptic Vesicles