1. ANATOMY AND PHYSIOLOGY OF THE CENTRAL NERVOUS SYSTEM
49
lesions of the tectum, and removal of the caudal and dorsal matrix zones,
only the basal portions of the tectum would regenerate. Regeneration
was initiated at the basal matrix cells. However, regeneration was less
extensive because the caudal matrix zone was absent. The caudal matrix
zone appeared to be most active in the regeneration of the optic tectum.
Regeneration would not occur if all of the matrix zones had been
removed by the operation. Richter (1965, 1966, 1968) has found mitoses
in the matrix layers of the optic tectum of Lebistes reticulatus and
Leucaspius &lineatus. Mitotic activity showed a rapid decrease in
zonal activity at the time of sexual maturity (Richter, 1966). This regenerative capacity of the optic tectum of fish was truly remarkable. The
fact that areas remain pluripotential throughout the life of the animal
and can redifferentiate ependymal cells into neuroblasts and spongioblasts was a unique phenomenon.
I. Axoplasmic Flow
Recent evidence has demonstrated that protcins produced in the perikaryon of neurons were transported by sol-gel changes in the neuron
to the bouton terminaux of the axon (Lubinska, 1964). Tritiated leucine
or histidine injected into the vitreous chamber of the goldfish or crucian
carp eye was incorporated into the perikarya of the ganglion cells of the
retina and transported to the axon terminations in the optic tectum
(Grafstein, 1967; Rahmann, 1968).
Radioactive leucine was transported along the goldfish ganglion cell
axon in a rapid component of 0.4 mm/day and a slow component that
arrived at the axon terminals for 23 days after injection ( Grafstein, 1967).
Tritiated histidine injected into the vitreous body of crucian carp and
zebra fish, Brachydanio rerio, was also transported biphasically ( Rahmann, 1967). There was a rapid interneuronal protein transport of
5.CL7.0 mm/day and a slow component that lasts up to 3 weeks. Three
weeks postinjection tritiated histidine was found in cerebrospinal fluid.
Deposition of tritiated thymidine in cerebrospinal fluid increased from
20 to 50% of the initial dose between 21 and 46 days.
In zebra fish following intraperitoneal injection of radioactive labelcd
phosphate in orthophosphate and tritiatrd histidine, cytidine and uridine
could be located in the perikarya of ncurons in the body of the cercbellum and the optic tectum (Rahmann, 1965, 1967). These amino acid
precursors were transported along the axon after incorporation into
macromolecular ribonucleic acid. Rahmann ( 1965) theorized that all
components for maintenance of the axon (mitochondria, neuronal ves-
49
lesions of the tectum, and removal of the caudal and dorsal matrix zones,
only the basal portions of the tectum would regenerate. Regeneration
was initiated at the basal matrix cells. However, regeneration was less
extensive because the caudal matrix zone was absent. The caudal matrix
zone appeared to be most active in the regeneration of the optic tectum.
Regeneration would not occur if all of the matrix zones had been
removed by the operation. Richter (1965, 1966, 1968) has found mitoses
in the matrix layers of the optic tectum of Lebistes reticulatus and
Leucaspius &lineatus. Mitotic activity showed a rapid decrease in
zonal activity at the time of sexual maturity (Richter, 1966). This regenerative capacity of the optic tectum of fish was truly remarkable. The
fact that areas remain pluripotential throughout the life of the animal
and can redifferentiate ependymal cells into neuroblasts and spongioblasts was a unique phenomenon.
I. Axoplasmic Flow
Recent evidence has demonstrated that protcins produced in the perikaryon of neurons were transported by sol-gel changes in the neuron
to the bouton terminaux of the axon (Lubinska, 1964). Tritiated leucine
or histidine injected into the vitreous chamber of the goldfish or crucian
carp eye was incorporated into the perikarya of the ganglion cells of the
retina and transported to the axon terminations in the optic tectum
(Grafstein, 1967; Rahmann, 1968).
Radioactive leucine was transported along the goldfish ganglion cell
axon in a rapid component of 0.4 mm/day and a slow component that
arrived at the axon terminals for 23 days after injection ( Grafstein, 1967).
Tritiated histidine injected into the vitreous body of crucian carp and
zebra fish, Brachydanio rerio, was also transported biphasically ( Rahmann, 1967). There was a rapid interneuronal protein transport of
5.CL7.0 mm/day and a slow component that lasts up to 3 weeks. Three
weeks postinjection tritiated histidine was found in cerebrospinal fluid.
Deposition of tritiated thymidine in cerebrospinal fluid increased from
20 to 50% of the initial dose between 21 and 46 days.
In zebra fish following intraperitoneal injection of radioactive labelcd
phosphate in orthophosphate and tritiatrd histidine, cytidine and uridine
could be located in the perikarya of ncurons in the body of the cercbellum and the optic tectum (Rahmann, 1965, 1967). These amino acid
precursors were transported along the axon after incorporation into
macromolecular ribonucleic acid. Rahmann ( 1965) theorized that all
components for maintenance of the axon (mitochondria, neuronal ves-