title: The presence of perforated synapses in the striatum after dopamine depletion, is this a sign of maladaptive brain plasticity?
abstract: Synaptic plasticity is the process by which long-lasting changes take place at synaptic connections. The phenomenon itself is complex and can involve many levels of organization. Some authors separate forms into adaptations that have positive or negative consequences for the individual. It has been hypothesized that an increase in the number of synapses may represent a structural basis for the enduring expression of synaptic plasticity during some events that involve memory and learning; also, it has been suggested that perforated synapses increase in number after some diseases and experimental situations. The aim of this study was to analyze whether dopamine depletion induces changes in the synaptology of the corpus striatum of rats after the unilateral injection of 6-OHDA. The findings suggest that after the lesion, both contralateral and ipsilateral striata exhibit an increased length of the synaptic ending in ipsilateral (since third day) and contralateral striatum (since Day 20), loss of axospinous synapses in ipsilateral striatum and a significant increment in the number of perforated synapses, suggesting brain plasticity that might be deleterious for the spines, because this type of synaptic contacts are presumably excitatory, and in the absence of the modulatory effects of dopamine, the neuron could die through excitotoxic mechanisms. Thus, we can conclude that the presence of perforated synapses after striatal dopamine depletion might be a form of maladaptive synaptic plasticity.
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Verónica
authors.initials: V
authors.lastname: Anaya-Martínez
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Ana Luisa
authors.initials: AL
authors.lastname: Gutierrez-Valdez
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Ordoñez-Librado
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Enrique
authors.initials: E
authors.lastname: Montiel-Flores
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Javier
authors.initials: J
authors.lastname: Sánchez-Betancourt
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: César
authors.initials: C
authors.lastname: Sánchez Vázquez del Mercado
authors.affiliation: Health Education Project, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Reynoso-Erazo
authors.affiliation: Health Education Project, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico.
authors.forename: Rocío
authors.initials: R
authors.lastname: Tron-Alvarez
authors.affiliation: Neuromorphology Lab, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex. 54090, Mexico nigraizo@unam.mx mariarosa@avila-costa.com.
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Avila-Costa
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D004298:Dopamine / Q000172:deficiency / Q000502:physiology*; D008297:Male; D008854:Microscopy, Electron; D009473:Neuronal Plasticity / Q000502:physiology; D016627:Oxidopamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*
chemical_list: D016627:Oxidopamine; D004298:Dopamine
keywords: dopamine deafferentation; perforated synapses; striatum; synaptology; ultrastructure