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Author(s): Brian O. Orr [1]; Richard D. Fetter [1]; Graeme W. Davis (corresponding author) [1] Homeostatic signalling systems ensure stable but flexible neural activity and animal behaviour [1, 2, 3, [...]

Author(s): Kira E. Poskanzer; Kurt W. Marek; Sean T. Sweeney; Graeme W. Davis (corresponding author) Neurotransmission requires a balance of synaptic vesicle exocytosis and endocytosis [1]. Synaptotagmin I (Syt I) [...]

A homeostatic hypothesis on maintaining the stability of neural function has been developed and suggests that intra/intercellular-signaling systems transduce information into regulated changes. Neurons are challenged with perturbations that can affect excitability during postembryronc development and all through life. Resulting changes can be in innervation, synaptic input and cell size. Neurons can compensate for the perturbations and maintain excitation levels using various compensation mechanisms including regulated changes of size/strength of synapses and ion channel function in the plasma membrane. .

Changes in the size of muscles during development are linked to the synaptic efficiency of motor neurons. One theory is that a signal from the muscle to the motor neuron maintains the link between the two. However, research has shown that there are two processes which control the effectiveness of single motor neurons. An increase in muscle innervation causes a reduction in presynaptic transmitter release and a reduction of muscle innervation causes an increase.

A restrictive definition of homeostasis is used to evaluate the phenomenological and molecular evidence for homeostatic signaling in nervous system. The analysis has proposed that homeostatic signaling will allow essential mechanisms of neural plasticity to persist but will constrain this plasticity to ensure that it drives constructive rather than destructive change.

The authors review publications on synapse disassembly. The topics include the analysis of phenomenology and mechanisms of this disassembly.