Retrograde axonal transport of horseradish peroxidase

Summary Eye muscles were examined histochemically for the presence of horseradish peroxidase (HRP) activity after intravenous injections of large doses of this tracer protein. HRP had penetrated through the blood vessels and diffused into the areas of motor end plates, where it outlined axon terminals at the synaptic clefts. HRP was incorporated into pinocytotic vesicles in the axons from where an intraaxonal transport in the retrograde direction to the nerve cell bodies in the brainstem followed. Accumulation of HRP in perikarya of motor neurons can therefore be the result of a physiological process of pinocytosis at the axon terminals. In this way exogenous macromolecules in the blood can by-pass the blood-brain barrier and reach the lower motor neurons in the CNS.     

Retrograde axonal transport of horseradish peroxidase in rats forebrain

The use of retrograde axonal horseradish peroxidase (HRP) transport in determining cells of origin of central fiber systems has been explored in young and adult rats by injecting HRP in different portions of the forebrain. After HRP injection in different cortical areas, HRP reaction granules were found in the neuronal cell bodies of the corresponding thalamic nuclei, while after injection into the caudate putamen HRP-positive granules were found also in the cell bodies of the parafascicular nucleus and the substantia nigra. It is concluded that the HRP injection method represents a promising technique for determining remote cells of origin of fiber systems in brains of young and adult rats and that it produces especially striking results when the material is examined under dark field illumination.     

Retrograde axonal transport of horseradish peroxidase from cornea to trigeminal ganglion

Summary Horseradish peroxidase (HRP) was dripped on the scarified left cornea of adult mice. Twentyfour hours later the animals were fixed by vascular perfusion and frozen sections cut from both trigeminal ganglia.After incubation for peroxidase activity labelled nerve cells were restricted to the medial ophthalmic part of the ganglion ipsilateral to HRP administration. If the scarification was omitted no neuronal labelling was observed. This labelling of the neurons is most probably the result from axonal uptake and subsequent retrograde axonal transport of the tracer.The similarity in distribution of peroxidase labelled nerve cells and the first ganglionic lesions occurring after instillation of herpes simplex virus in the cornea is pointed out.     

Retrograde axonal transport of horseradish peroxidase by ganglion cells of the albino rat retina

After introduction of small amounts of horseradish peroxidase (HRP) into known visual centers of the brain, retinal ganglion cells projecting to these regions were detected by the accumulation of HRP-positive granules in their somata. Control experiments indicated that the HRP-positive granules had reached the ganglion cell somata by retrograde axonal transport, and did not represent blood-borne or endogenous peroxidase. Using this technique, it has been determined that axons of both large and medium-sized neurons in the ganglion cell layer of adult and immature rat retinae terminate in the superior colliculus and lateral geniculate body, and that characteristic displaced ganglion cells with axonal connections to these visual centers occur regularly in these retinae. In addition, certain small cells in the retinal ganglion cell layer are described which may represent glia or interneurons, or ganglion cells which lack the ability to transport peroxidase or which lack central connections to these visual centers of the brain.     

Retrograde intraaxonal transport of horseradish peroxidase by neurons in octopus

While retrograde axonal transport is the basis of a widely used neuroanatomical method, it has been rigorously demonstrated in vivo only in a few vertebrate species and not yet in an invertebrate. Evidence is presented that motor neurons of the octopus stellate ganglion are capable of retrograde intraaxonal transport of horeseradish peroxidase. This demonstration shows that retrograde transport occurs in widely divergent groups of animals, and may be a general property of neurons.     

Retrograde transport of horseradish peroxidase in the magnocellular neurosecretory system of the rat.

Horseradish peroxidase (HRP) was injected into the pituitary in adult rats. After 2-3 days, the neurones of the supraoptic nuclei, the magnocellular parts of the paraventricular nuclei, and the various accessory neurosecretory hypothalamic nuclei showed accumulation of HRP. The HRP reaction product consisted of fine, discrete cytoplasmic granules, and in electron micrographys it was seen to be located in the lysosome-like dense bodies of 0.4-0.6 mum diameter which are normally present in the cytoplasm of the neurosecretory neuron.es. Very little reaction product was found in the neurosecretory axons. Reaction product was also found in the hypothalamic arcuate nuclei. This was the result of an endogenous peroxidase-like activity, since it occurred in control animals which had not received HRP. This endogenous reaction product is non-neuronal. Morphologically, it takes the form of distinctive clusters of coarse granules which are seen in electron micrographs to be characteristic angular bodies of 0.7-1.0 mum diameter located in the cytoplasm of astrocytes or their processes.     

Increased axonal transport in peripheral nerves of thiamine-deficient rats

Thiamine deficiency has been implicated as a significant contributing factor in the development of peripheral neuropathies in chronic alcoholic patients. We hypothesized that thiamine deficiency may lead to an alteration in axonal transport because it has been associated with "dying-back" neuropathies and its importance in neural tissue has been demonstrated with antimetabolites. To test this possibility rats were made thiamine-deficient by feeding a liquid diet lacking thiamine. Control rats were pair-fed a complete liquid diet. The deficiency developed after 3 to 4 weeks and was evidenced by anorexia, weight-loss, and a significant increase in the erythrocyte transketolase activity ratio. Also, the sural nerve conduction velocity was found to be significantly reduced in these animals (18.74 m/s) relative to that of pair-fed control rats (31.99 m/s). In vitro transport experiments utilizing dorsal root ganglia-sciatic nerve preparations indicated that twice as much [35S]methionine-labeled protein accumulated at a ligation by fast transport in the thiamine-deficient rats as in nerves of their pair-fed controls. There was no difference in the level of incorporation of radioactive precursor into the dorsal root ganglia. The increase in transport suggests that thiamine deficiency per se has no detrimental effects on the transport machinery and process, but may indicate extensive regenerative activity in the distal portions of these axons.     

Retrograde transport of horseradish peroxidase in transected axons. 1. Time relationships between transport and induction of chromatolysis

Horseradish peroxidase applied to the traumatized area of a crushed or a cut facial nerve of mice accumulated in the neuronal perikarya of the facial nucleus 6 h after the application. This accumulation is probably the result of uptake of the protein tracer in axons proximal to the trauma, followed by intraaxonal transport in the retrograde direction. The protein tracer arrived in the perikarya prior to the earliest described response of these neurons to axonal injury. In this respect different hypotheses involving a disturbed retrograde transport of macromolecules for eliciting chromatolysis of peripheral neurons following injury to their axons are reviewed.     

Projections of lamprey spinal neurons determined by the retrograde axonal transport of horseradish peroxidase.

The spinal cords of larval sea lampreys (Petromyzon marinus) and adult river lampreys (Ichthyomyzon unicuspis) were injected with horseradish peroxidase through a transection 1 cm caudal to the last gill. Some animals also had a spinal hemisection 1 cm caudal to the injection. After recovery periods of 1 to 52 days, the spinal cords were treated with diaminobenzidene and hydrogen peroxide, and the projections of various cell types determined in wholemount slides. From these observations the following conclusions were drawn. Most dorsal cells (primary sensory cells) are bipolar with a long rostral projection and a short caudal projection of no more than 5-10 mm. Both processes travel in the ipsilateral dorsal column. Their peripheral processes enter the dorsal roots as branches of their central axons. Some dorsal cells send processes out three or more dorsal roots both rostral and caudal to the cell body. Myotomal motoneurons have characteristic locations in the medial gray column and send prominent transversely oriented dendrites into the lateral columns. A few motoneurons are unusually large. In addition to giant interneurons the majority of smaller rostrally projecting interneurons also have decussating axons. A recently described cell type, the oblique bipolar cell, appears to have an exclusively crossed rostral projection. Although most edge cells project rostrally, as many as 20% may have a caudal projection or both rostral and caudal projections. Edge cells project equally to the ipsilateral and contralateral spinal hemicord, but their processes do not extend more than about 18 mm in sea lamprey larvae and 37 mm in adult river lampreys. Lateral cells project exclusively to the ipsilateral caudal hemicord. A few cells which resemble lateral cells in location and in possessing large lateral dendrites, project rostrally. However, these have atypical morphologic features which probably distinguish them from true lateral cells. Thus far, regardless of cell type, all decussating axons seem to pass ventral to the central canal, while decussating medial dendrites pass dorsally.     

Retrograde axonal transport of mercury

Female Wistar rats were injected in the tongue with a small volume of 203Hg and were killed 2 weeks later. The lower brain stem with the hypoglossal nuclei was removed and sectioned in a cryostat. Autoradiography of freeze-dried sections showed labeling of both hypoglossal nuclei. The results are regarded as strong evidence of retrograde axonal transport of mercury in the hypoglossal nerve.