摘要:

AbstractSDS‐polyacrylamide gel electrophoresis was used to characterize labeled proteins transported in rat motor and sensory axons after application of 3H‐leucine to the neuron cell bodies. Two types of experiments were performed: first, transported protein accumulating proximal to a ligature placed on the sciatic nerve was analyzed; second, the segment of sciatic nerve nearest to the “lwavecrest” of transported protein travelling down the nerve was analyzed. In both cases, no significant differences in peak position or amplitude were found in gels containing labeled proteins from motor or sensory axons. This may mean that the majority of fast‐transported protein is involved in an axonal function common to the two types

ISSN:0022-3034    

DOI:10.1002/neu.480080403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractProteins synthesized by soma located inL4dorsal root ganglia and supplied to the axonal branches extending centrally in the dorsal root and peripherally towards the sciatic nerve were analyzed for radioactivity following injections of [3H] leucine into the L4dorsal root ganglia. All proteins located in the dorsal root and sciatic nerve were analyzed by SDS acrylamide gel electrophoresis at various times post injection. The differences in radioactivity between the dorsal root and sciatic nerve proteins were mainly quantitative and not qualitative, with many proteins of various molecular weight ranges being transported into both segments. Generally, it appears that in both axonal branches the high molecular weight proteins are transported at the highest rate, medium weights slower and low molecular weight proteins slowest. More proteins of high and low molecular weights are transported into the dorsal root whereas more of those of medium molecular weight are transported towards the sciatic nerve.

ISSN:0022-3034    

DOI:10.1002/neu.480080404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractThe anterior extrinsic protractors in the buccal mass ofAplysiaare symmetrical sheets of branching bundles of muscle fibers which form an electrical syncytium. The addition of potassium or cholinergic, adrenergic, and glutaminergic agonists to the sea water bathing medium produces contracture of the muscle.Strychnine and cholinergic or adrenergic antagonists all block contractures produced by cholinergic and adrenergic agonists but not those produced by potassium or glutamate.Iontophoretic application through microelectrodes of acetylcholine or dopamine anywhere on the muscle surface produced a graded depolarization of the membrane. By contrast, glutamate produces depolarization only at discrete membrane sites. Endogeneous contractions often appeared spontaneously or could be induced by drug exposure. ATP inhibits endogeneous contractions.

ISSN:0022-3034    

DOI:10.1002/neu.480080405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractNewborn rats were treated at different stages of their development with low doses of methylazoxymethanol acetate. The postnatal increase of the DNA content of the cerebrum did not differ from that of controls. In the cerebellum, the DNA content was transitorily reduced, but later, the external granular layer became thicker and DNA deposition increased in comparison with controls; finally, the cerebellar DNA returned to a normal value. Morphological abnormalities of the cerebellum, abnormal orientation of migrating cells, scattering of Purkinje cell bodies within the internal granule cells and specially striking abnormalities of the morphology and orientation of Purkinje cell dendrites were noted in rats treated with MAM from birth to day 3. The effects on the Purkinje cell morphogenesis persisted but were much less marked when MAM was given from 4 to 7 or from 8 to 11 days. Neonatal thyroid deficiency, as MAM‐treatment between days 0 and 3, leads to an abnormal position of Purkinje cell bodies within the cerebellar cortex; it also leads to morphological abnormalities of their dendritic arborization which closely resemble those observed after MAM‐treatment during the second postnatal week. It also alters the cell formation in the cerebellum. Thyroid deficiency probably exerts its effect on cell formation earlier than previous biochemical studies have shown. On another hand, the morphological abnormalities of Purkinje cell arborizations in the thyroid‐deficient animals may be partly due to the perturbations of cell formation which persist later in the cereb

ISSN:0022-3034    

DOI:10.1002/neu.480080406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractAcrylamide is a neurotoxin known to impair regeneration of axons following nerve crush and to produce structurally abnormal regenerating sprouts. To investigate the mechanism of these abnormalities, protein synthesis and fast axonal transport were studied in acrylamide‐intoxicated and control rats 2 weeks after sciatic nerve crush. Using anin vitropreparation of sciatic nerve‐dorsal root ganglion, there was no difference in ganglion3H‐leucine incorporation between the two groups. In these preparations of sensory axons, as well as in motor axons studiedin vivo, a smaller proportion of rapidly transported radioactivity was carried beyond the crush in the acrylamide‐regenerating nerves compared to the control‐regenerating nerves. Correlative ultrastructural studies demonstrated that this difference reflected the impaired outgrowth of the acrylamide‐regenerating nerves, rather than an abnormality in fast transport. The acrylamide‐treated sprouts often developed swellings filled with whorls of neurofilaments; in addition, many sprouts ended in massively enlarged growth cones containing membranous organelles. EM autoradiography showed labeled, rapidly transported organelles accumulated in the neurofilamentous whorls, and therefore suggested that these organelles might be “trapped” or impeded in passage through these regions. However, there was no evidence that the growth cones received insufficient amounts of transported protein; in fact, the distended endings were densely labeled and apparently “ballooned” by transported organelles.These results suggest that acrylamide intoxication does not impair regeneration by diminishing the delivery of rapidly transported materials to the growing tip. Rather, the marked distention of the growth cones is interpreted as the morphological consequence of continued delivery of rapidly transported organelles into sprouts unable to util

ISSN:0022-3034    

DOI:10.1002/neu.480080407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effects of agents known to affect the cyclic AMP (cAMP) system in nervous tissue have been studied on the rapid axonal transportin vitroof [3H]leucine‐labeled proteins in the frog sciatic nerve. The transport was inhibited by 3 different cAMP analogues; dibutyryl cAMP (1 mM), zeatin (0.5 mM), and zeatin riboside (0.5 mM), whereas another N6‐substituted adenine derivative, N6‐, isopentyl‐adenine (DMA) (0.5 mM), and also dibutyryl cyclic GMP (1 mM), lacked effects. Two inhibitors of cAMP phosphodiesterases, papaverine and RO 207222, increased the level of cAMP in the nerve and arrested the transport. Papaverine was very potent and caused a reversible transport block at 0.05 mM.Adenosine (3 mM) increased the cAMP content about 16 times, much more than any of the other drugs tested, but only inhibited the transport by about 50%. Veratridine, a depolarizing agent, irreversibly blocked the transport at a low concentration (0.01 mM), which did not change the cAMP level.Transport inhibitory effects by another depolarizing substance, ouabain, and tricyclic psychotropic agent, chlorpromazine, have been described earlier. Ouabain (0.1 mM), in contrast to chlorpromazine (0.1 mM), caused a small increase in the cAMP content.The present results do not suggest the existence of a close relationship between rapid axonal transport and the cAMP system. Transport inhibitory effects due to disturbed energy metabolism will be di

ISSN:0022-3034    

DOI:10.1002/neu.480080408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractCortical spreading depression (CSD) was elicited by focused ultrasonic irradiation (800 kHz) of exposed cerebral cortex in anesthetized rats. With the acoustic output of 0.65 W at the probe‐tissue contact (3 mm in diameter), CSD was elicited after 28‐sec irradiation in normothermic rats. Reduction of cortical temperature to 31°C increased the threshold irradiation time to 82 sec on the average. Ten‐ to thirty‐sec heating of cerebral cortex with a thermode elicited CSD when surface temperature exceeded 47°C. Histological examination of the cortical areas exposed to threshold irradiation revealed a central coagulation lesion surrounded by edema. It is concluded that the ultrasonic irradiation elicits CSD by dissipated heat. Differences in threshold duration of irradiation in hypothermic and normothermic rats were used to compute the threshold temperature which had to be exceeded in the critical volume of cortex in order to

ISSN:0022-3034    

DOI:10.1002/neu.480080409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480080410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480080411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480080412

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY