Variation in the number and size of myelinated nerve fibers regenerated after repeated localized freezing of the sciatic nerve of rats]

The number and size of myelinated fibres have been determined in the nerve to medial head of the gastrocnemius muscle of Rats in which the sciatic nerve had been frozen locally 1 to 5 times at monthly intervals. The contralateral nerve was used as a control. When the measurements were made one month after the last freezing, the number of fibres increased progressively until the 3rd freezing, reaching about 220% of the normal value. No higher values were observed after 4 or 5 freezings. The mean diameter of fibres decreased with the number of operations. When the measurements were made 3, 6, 12 or 18 months after the 3rd freezing, the number of fibres decreased by about 30% between the 1st and the 3rd month and then stabilized. The mean diameter of fibres increased progressively. However, at the 18th month, the size of the myelinated fibres had not reached the normal value.     

Changes in cholinesterase activity of muscle after crushing the sciatic nerve of rats

The subcellular distribution of cholinesterase (ChE) was studied in the gastrocnemius muscle of rats after strong or weak nerve crushing. The ChE activities of muscle were decreased to a greater extent by strong crushing than by weak crushing. In particular, the ChE activity of the fraction containing sarcoplasmic reticulum was most greatly decreased. These results suggest that the change in the ChE activity of the microsomal fraction most finely reflects the strength of nerve crushing.     

Changes in cholinesterase activity of muscle after crushing the sciatic nerve of rats

Summary The subcellular distribution of cholinesterase (ChE) was studied in the gastrocnemius muscle of rats after strong or weak nerve crushing. The ChE activities of muscle were decreased to a greater extent by strong crushing than by weak crushing. In particular, the ChE activity of the fraction containing sarcoplasmic reticulum was most greatly decreased. These results suggest that the change in the ChE activity of the microsomal fraction most finely reflects the strength of nerve crushing.Acknowledgments. This study was accomplished in Central Research Laboratories, Sankyo Co. Ltd. The authors wish to thank Prof. Tsuneyuki Nakazawa, Department of Neuropsychiatry, School of Medicine, Fujita-Gakuen University, and Dr Yutaka Sakai for their valuable advice and support, Sr Jean M. Michalec for her critical comments, and Miss Hamako Katano, Mr Naoji Mikuni and Miss Yoshie Ishii for their skillful technical assistance.     

Dissolution of the pulmonary collagen of the normal rat by repeated pepsin action]

A non-denaturating method of extracting collagen from Rat lungs was developed. It consists in dissolving the collagen by repeated action of pepsin. Depending on the age of the animal, efficiency values between 50 and 90% are obtained.     

Is tubulin involved in the electrically-induced mechanical activity of the isolated rat sciatic nerve?

Summary The electrically-induced mechanical activity of isolated segments of rat sciatic nerves remains unaffected following incubation with 10^–4 M colchicine, vinblastine or melatonin. Vinblastine depressed tubulin levels in incubated nerves. These results suggest that microtubules are not involved in nerve mechanical activity in vitro.This work was supported by grant No. 6638 from the CONICET (Argentina). It is dedicated to the memory of C.E. Valenti, decreased November 1979.     

Formation of lipoperoxide in isolated sciatic nerve by chinoform-ferric chelate

Summary Effects of chinoform and chinoform-ferric chelate on formation of lipoperoxide in isolated sciatic nerve were investigated. Free chinoform did not increase the lipoperoxide level, while chinoform-ferric chelate significantly increased it. Assuming that the lipoperoxide formed denatures the associated protein in the nerve, the effect of chinoform-ferric chelate could explain, at least partly, the demyelination of nerve tissues caused by massive doses of chinoform.     

‘Compensatory’ muscle hypertrophy in the rat induced by tenotomy of synergistic muscles

Zusammenfassung Nachweis, dass die schnelle Hypertrophie des M. soleus nach Tenotomie des synergistischen M. gastrocnemius durch passive Spannung des antagonistischen Muskels verursacht wird. Denervierung dieser Antagonisten verzögert eine Hypertrophie des M. soleus, während die Deafferenzierung des ganzen Gliedes ohne Effekt bleibt; auch zusätzliche Arbeitsleistung führt auf dem Höhepunkt der Hypertrophie zu keinerlei Gewichtszunahme.     

Effect on macrophages of acute stress induced in mice by local irradiation]

In examining the role of radiation in inducing immunosuppression in tumor-bearing Mice it has been shown that the experimental acute stress inadvertently generated by the procedure is profoundly immunosuppressive. It would appear that monocytes under the influence of glucocortico?ds are sequestered in the spleen. This monocyte immobilisation leads to rapid suppression of local inflammatory reactions including delayed hypersensitivity. The increased number of marcrophages in the spleen is co-incident with non-specific non T cell splenocyte anti-tumour activity. Stress induced suppression of inflammation is prevented by previous adrenalectomy and restored by hydrocortisone.     

Formation of lipoperoxide in isolated sciatic nerve by chinoform-ferric chelate.

Effects of chinoform and chinoform-ferric chelate on formation of lipoperoxide in isolated sciatic nerve were investigated. Free chinoform did not increase the lipoperoxide level, while chinoform-ferric chelate significantly increased it. Assuming that the lipoperoxide formed denatures the associated protein in the nerve, the effect of chinoform-ferric chelate could explain, at least partly, the demyelination of nerve tissues caused by massive doses of chinoform.     

Modifications of the vestibular nerve activity by stimulation of the efferent vestibular system

Riassunto La stimolazione elettrica della zona nucleare vestibolare in vicinanza del nucleo di Deiters (dove presumibilmente originano le fibre efferenti vestibolari) è seguita, dopo un periodo di latenza pressochè costante (22–32 msec), dalla comparsa di potenziali bioelettrici nel nervo vestibolare controlaterale.     

Role of granular cells in the placement and distribution of synapses between ascending fibers and Purkinje cells of the rat cerebellum]

The study of rats irradiated during development shows that the establishment of the one-to-one relationship in the adult between climbing fibers and Purkinje cells which follows the immature multiply innervated stage mainly depends on granule cells formed before day 8. Climbing fibers ending upon a multiply innervated cell are intermingled on the same dendritic segments.     

Stimulation by caffeine of the calcium efflux in barnacle muscle fibers

Zusammenfassung Die Befunde ergeben, dass einzelne Muskelfasern der Entenmuschel durch Mikroinjektion mit⁴⁵Ca aufgeladen werden können. Eine Umspülung der Muskelfasern mit einer coffeinhaltigen Lösung bewirkt ein stärkeres Ausströmen des Calciums als eine Mikroinjektion des Coffeins in die Fasern direkt.     

An analysis of the distribution of the myelinated nerve fibers in the optic fascicle of a beagle dog

The composition of both optic fascicles of a Beagle dog was studied in topographically oriented, semithin transections of whole nerve stained with toluidine blue. About 165,000 myelinated fibers were present in each nerve, their maximum caliber reaching 11 micron; large, less densely arranged fibers occurred especially in the dorso-temporal region.     

An analysis of the distribution of the myelinated nerve fibers in the optic fascicle of a Beagle dog

Summary The composition of both optic fascicles of a Beagle dog was studied in topographically oriented, semithin transections of whole nerve stained with toluidine blue. About 165,000 myelinated fibers were present in each nerve, their maximum caliber reaching 11 m; large, less densely arranged fibers occurred especially in the dorso-temporal region.We are grateful to Dr D.C. Naylor, Mrs K. Schnider, Mr F. da Silva and Mr K. Traber for their aid.