Professor Bruce McEwen discusses the remodeling of dendrites, which are affected by BDNF, TPA, cell-adhesion molecules, and a number of other factors.
We know best for the hippocampus, and so Iâ€™ll talk about that. We know that the shrinkage of dendrites is produced by excitatory amino acids, which probably help to destabilize the cytoskeleton, but you need circulating glucocorticoids around, and you also need enough BDNF [brain-derived neurotrophic factor] around to make it possible for this to occur. We suspect that, at least in some parts of the brain, thereâ€™s another molecular system, called the tissue plasminogen activator [TPA], which is as it sounds, it helps in the blood clotting or in hydrolyzing blood clots, but these are also proteases that are released from nerve cells, and they probably work independently of their protease activity as signaling molecules. If you donâ€™t have TPA, you donâ€™t have stress-induced loss of spines of synapses in the hippocampus, and so the animal actually is resilient or resistant to the effects of stress â€“ the short-term effects of stress â€“ on memory. Thereâ€™s another class of molecules called the cell adhesion molecules, and they are involved probably in facilitating signaling processes, theyâ€™re also perhaps involved in how sticky cells are â€“ whether they will retract and be able to move â€“ and this molecule is also essential for dendritic remodeling. I suspect there are many, many more molecules, so it isnâ€™t simply something that is driven by your stress hormones alone. There are the stress hormones working in a permissive sense, along with a lot of other processes.
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Professor Bruce McEwen introduces BDNF, a class of neurotrophic molecules released by excitatory neurotransmission and associated with key process and disorders.
Professor Wayne Drevets describes dendritic atrophy, which refers to reductions in the branching of neurons.
Professor Bruce McEwen describes the interplay between reilience and stress, which can cause the brain to shrink or grow.
Professor Kenneth Kosik discusses some of the key issues relating to local changes at the synapse that mediate learning. RNA is particularly important in this regard.
Professor Kenneth Kosik discusses changes in synapses that accompany long-term potentiation, which include enlarged dendritic spines.
Professor Bruce McEwen discusses differences between the sexes in coping with stress. These are mediated by hormonal, neural, and genetic factors.
Professor Wayne Drevets discusses specific types of learning deficits associated with depression. These may be caused by biochemical impairments in long-term potentiation.
The idea that drug addiction is a result of 'learning gone wild' was bolstered by several reports.
Professor Bruce McEwen describes the blood-brain barrier, which prevents most proteins from accessing the brain. Selective proteins can cross the barrier, instigating processes such as neurogenesis.
GABA is the main inhibitory neurotransmitter in the adult brain. GABRA3 is a candidate gene for autism.