Neurons lose intrinsic axon regenerative ability with maturation, but the mechanism remains unclear. Using an in-vitro laser axotomy model, we show a progressive decline in the ability of cut CNS axons to form a new growth cone and then elongate. Failure of regeneration was associated with increased retraction after axotomy. Transportation into axons becomes selective with maturation; we hypoth...

We have examined the dendritic and axonal ultrastructure of intact anterior bulbar reticulospinal neurons (ABCs) in the CNS of the larval sea lamprey and compared it with that of the dendrites and neuritic sprouts from ABCs examined 2 months following axotomy. Dendrites and axons of intact ABCs are distinguishable from one another by several ultrastructural criteria: (1) the predominance of mic...

Abdulla, Fuad A. and Peter A. Smith. Axotomyand autotomyinduced changes in Ca and K channel currents of rat dorsal root ganglion neurons. J Neurophysiol 85: 644–658, 2001. Sciatic nerve section (axotomy) increases the excitability of rat dorsal root ganglion (DRG) neurons. The changes in Ca currents, K currents, Casensitive K current, and hyperpolarization-activated cation current (IH) that may...

Zhang, Jun-Ming, David F. Donnelly, Xue-Jun Song, and Robaxonal connections, thereby allowing the measurement of ert H. LaMotte. Axotomy increases the excitability of dorsal root conduction velocity while minimizing potential alterations ganglion cells with unmyelinated axons. J. Neurophysiol. 78: in cellular phenotype due to culture conditions or removal 2790–2794, 1997. To better understand t...

The transformation of a stable axonal segment into a motile growth cone is a critical step in the regeneration of amputated axons. In earlier studies we found that axotomy of cultured Aplysia neurons leads to a transient and local elevation of the free intracellular Ca2+ concentration, resulting in calpain activation, localized proteolysis of submembranal spectrin, and, eventually, growth cone ...

Axotomy of the peripheral axon of dorsal root ganglion (DRG) cells is known to result in chromatolysis and changes in protein synthesis in DRG cells. We investigated whether a stimulus produced by peripheral branch axotomy would affect the regenerative properties of both the central and peripheral axon of the DRG cell equally. To examine this question, a conditioning crush lesion was made dista...

After axotomy, expression of acetylcholinesterase (AChE) is greatly reduced in the superior cervical ganglion (SCG); however, the molecular events involved in this response remain unknown. Here, we first examined AChE mRNA levels in the brain of transgenic mice that overexpress human HuD. Both in situ hybridization and reverse transcription-PCR demonstrated that AChE transcript levels were incr...

The cell body of the medial giant interneuron (MGI) in the cricket normally does not spike in response to injected depolarizing currents. When axotomized 1 mm or more from the cell body (distant axotomy), the membrane properties of the soma remain unchanged. However, after axotomy close to the cell body (200 to 500 micron), the soma membrane becomes capable of generating action potentials by 6 ...

Axonal regeneration can occur within hours of injury, the first step being the formation of a new growth cone. For sensory and retinal axons, regenerative ability in vivo correlates with the potential to form a new growth cone after axotomy in vitro. We show that this ability to regenerate a new growth cone depends on local protein synthesis and degradation within the axon. Axotomy in vitro lea...

Peripheral axotomy induces long-term hyperexcitability (LTH) of centrally located sensory neuron (SN) somata in diverse species. In mammals this LTH can promote spontaneous activity of pain-related SNs, and such activity may contribute to neuropathic pain and hyperalgesia. However, few axotomized SN somata begin to fire spontaneously in any species, and why so many SNs display soma LTH after ax...