Developmental dynamics of Purkinje cells and dendritic spines in rat cerebellar cortex

Abstract

Quantitative morphological changes of the developing Purkinje cells were studied from 6 to 90 postnatal (PN) days in the IVth lobule of vermis in the cerebellum of rats. The soma size (mean diameter) of Purkinje cells increased rapidly between 6 PN (on average 10 microns) and 18 PN (about 17 microns) days; it did not change between 18 and 25 PN days, but increased moderately again between 25 and 48 PN days (22-23 microns) and stabilized on the same value. In contrast, the number of Purkinje cells/100 microns (the "linear density") decreased rapidly from 6 to 18 PN days. The molecular layer area belonging to 1 Purkinje cell increased rapidly from 6 to 25 PN days (from about 370 to 6,200 microns 2) and less rapidly between PN days 30 to 48 (up to 9,300 microns 2), followed by a moderate decrease at PN day 90 (about 6,600 microns 2). The volume belonging to 1 Purkinje cell dendritic arbor was about 5,500 microns 3 at PN day 6, 93,000 microns 3 at PN day 25, and 100,000 microns 3 at PN day 90. The numerical density of dendritic spines in the molecular layer showed a biphasic curve: a rapid increase from PN days 6 to 21 followed by a significant but short decrease at PN day 25, moderate rise from PN days 25 to 48, and a subsequent decline between PN days 48 and 90. The number of spines belonging to 1 Purkinje cell showed two developmental "peaks": the first peak at 21 PN days was moderate (5.6 x 10(4) spines/Purkinje cell) while the second maximum at 48 PN days was more significant (1.2 x 10(5) spines/Purkinje cell), which then declined to 6.3 x 10(4) spines/Purkinje cell at PN day 90. It is suggested that the temporary overproduction and the following decline in the number of Purkinje dendritic spines during the development of the cerebellar cortex may be the morphological indicator of the dynamics of synaptogenetic and of synaptic stabilization processes.

Ontogenetic Alterations in Molecular and Structural Correlates of Dendritic Growth after Developmental Exposure to Polychlorinated Biphenyls

“…The size of the Purkinje cell soma was not affected by PCB exposure (PND22: controls, 406 μm 2 ± 11; PCB-treated, 386 μm 2 ± 9; PND60: controls, 334 μm 2 ± 12; PCB-treated, 334 μm 2 ± 7), suggesting that the decreased dendritic field was not due to general cellular atrophy. Consistent with previous reports (Takacs and Hamori 1994), a general maturation with an increase in the dendritic arbor and spine density was seen in both groups (Figure 4). At PND60, the difference between the two groups was no longer evident and there were no significant differences in Purkinje cell dendritic area between treatment groups (Figure 4E).…”

Ablation of Glutamate Receptor GluRδ2 in Adult Purkinje Cells Causes Multiple Innervation of Climbing Fibers by Inducing Aberrant Invasion to Parallel Fiber Innervation Territory

“…It is during the second postnatal week that PF synapses are formed enormously onto spines of growing PC dendrites in wild-type rodents (Woodward et al, 1971;Sotelo, 1978;Takács and Hámori, 1994), and that free spines increase drastically in global GluR␦2-knockout mice . Furthermore, it is also during this period that a single "winner" CF translocates to PC dendrites (Hashimoto et al, 2009).…”

Impact of Geometrical Characteristics of the Organellar Store and Organelle-Free Cytosol on Intracellular Calcium Dynamics in the Dendrite: a Simulation Study

“…The ER is a structurally dynamic organelle; its size and shape can vary depending on different physiological states [18,20]. Similar structural (geometrical) variability is also an inherent characteristic of the spines [21][22][23].…”