Age-dependence in the homeostatic upregulation of hippocampal dendritic spine number during blocked synaptic transmission.

摘要: Homeostatic regulation of spine number in mature hippocampal neurons results more dendritic spines when synaptic transmission is blocked, providing a mechanism to compensate for diminished input. It unsettled whether blockade also elevates during development. To address this question, was blocked rat slices critical developmental stages formation at postnatal days (P) 6–P22 and compared adults. CA1 pyramidal cells were labeled with DiI maintained 5 h one three conditions, control artificial cerebrospinal fluid (ACSF), block media containing antagonists ACSF, or nominally calcium-free ACSF high magnesium. Slices fixed mixed aldehydes, sectioned, the lateral dendrites imaged stratum radiatum confocal microscopy. Dendritic density quantified per unit length dendrite. At P6–7 there only few protrusions emerging from dendrites, which predominantly filopodia-like appearance. both P11–12 P15–16 mixture structures. By P20–22 predominated about 82% adult level. increased as adults, but unchanged younger ages. When extracellular calcium zero, further on In contrast, decreased along under zero condition. Under longer than all other ages, did not differ another. elongated only. condition transmission, shortened These findings reveal age-dependent changes manifestation homeostatic that could be mediated by maturational mechanisms regulating postsynaptic calcium.