Squeezing dendritic necks

Squeezing dendritic necks Sure enough, diffusion restriction was induced in individual dendrites by pairing two excitatory signals from pre-synaptic and postsynaptic sources. The clampdown at the dendrite neck may involve cross-linking of an actin mesh, or blockage by mitochondria or smooth endoplasmic reticulum. Either way, says Sabatini, “if a spine can hold onto [molecules such as] active kinases, this will have a big impact on signal integration.” An isolated spine may be able to retain activated messengers until the next electrical spike arrives to boost the signal further. And truly isolated spines may also be able to act as independent electrical units that store or boost sub-spike electrical inputs. Reference: Bloodgood, B.L., and B.L. Sabatini. 2005. Science. 310:866–869. Over time (left to right), individual dendrites allow the escape of proteins (green) quickly (top), slowly (middle), or hardly at all (bottom). SA BA TI N I/ N A S