摘要:

AbstractLimulusventral photoreceptors are vitally stained by neutral red. In other systems such staining has been correlated with the presence of monoamines or neuropeptides. The stained cellular components in ventral photoreceptors are clusters of small ovoids which have been identified as residual bodies. These structures are unlikely candidates for monoamine or neuropeptide synthesis or storage sites, but may be part of the cyclic synthesis and degradation of photosensitive membrane. While vital staining with neutral red is a particularly useful method for identifying certain classes of neuronsin vivo, in the case of ventral photoreceptors, the association of the vital staining property with the presence of a particular class of neurotransmitter candidates has proven difficult. Neutral red is useful, however, for visualizing the segmentation of ventral photoreceptorsin vivo.

ISSN:0022-3034    

DOI:10.1002/neu.480150202

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

年代:1984

数据来源: WILEY

摘要:

AbstractUsing the desheathed nerve preparation, a pyroantimonate precipitation method was used to examine the distribution of electron‐dense particles seen in various organelles of the nerve fibers following exposure of nerve to various levels of Ca2+in vitro. The presence of Ca2+in the electron‐dense particles was indicated by their extraction with EGTA and by the use of energy‐dispersive X‐ray microanalysis.In normal Ringer or in a Ca2+‐free medium, electron‐dense particles were seen associated with the outer membrane of the mitochondria, with the smooth endoplasmic reticulum (SER), along the axolemma and yet others scattered throughout the axoplasm.When nerves were incubated in media containing higher than normal concentrations of 20–60 mMCa2+, an increase in the number of such electron‐dense particles was seen in the axoplasm and within the mitochondrial matrix. Nerves loaded with a high concentration of 60mMCa2+could be depleted of these particles after transfer to a Ca2+‐free or low Ca2+Ringer medium.The sequenstration of Ca2+in axonal organelles is discussed with respect to Ca2+‐regulatory mechanisms in the axon needed to maintain a low level of Ca2+which is optimal for the support of a

ISSN:0022-3034    

DOI:10.1002/neu.480150203

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

年代:1984

数据来源: WILEY

摘要:

AbstractAfter axotomy, changes in the composition of fast axonally transported proteins (FTP) within the peripheral nervous system (PNS) axons have been reported. The most significant and reproducible changes involved polypeptides found within the molecular weight range of 31.0 to 14.5 kilodaltons (Bisby, 1980). We wished to determine whether similar changes following axotomy occur in axons of the central nervous system (CNS). Intracranial axotomy of the left optic tract was performed stereotaxically in rats. Six days post axotomy 50 μCi35[S]‐methionine was injected into the vitreous body of both eyes. FTP were isolated within the optic nerves 2 h after isotope injection. The nerve segments were processed for SDS‐PAGE, fluorography, and compared to similarly prepared fluorographs of normal and eight day postaxotomy sciatic nerve segments. The labelling of 5 major polypeptide bands (S1, MW ≃ 28,000; S2a, MW ≃ 25,000; S2b, MW ≃ 23,000; T1, MW ≃ 20,200; and T2, MW ≃ 17,000) was studied by laser densitometry. Band S2bshowed a highly significant (p<0.001) increase in concentration, while bands S1and T1demonstrated highly significant decreases in concentration following axotomy of the sciatic nerve. In contrast, after axotomy of the retinal ganglion cell axons the only significant change was a decrease (p<0.05) in T1. We suggest that failure of CNS axons to respond similarly to PNS axons following axotomy may be related to the failure of CNS axons

ISSN:0022-3034    

DOI:10.1002/neu.480150204

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe activity and isoenzyme pattern of muscle lactic dehydrogenase (LDH) was measured at different times after axonal transport blockade by colchicine or after denervation. After denervation, total LDH activity decreased and the isoenzyme pattern was altered, LDH‐1 being the most affected form. In contrast, after axonal transport blockade there was a decrease in LDH activity but the isoenzyme pattern was not modified. Denervation abolishes both nerve‐evoked muscle activity and the release of neuro trophic substances from the nerve whereas colchicine blocks axonal transport without affecting the nerve capacity to conduct action potentials or neuromuscular transmission. It is then concluded that nerve‐evoked muscle activity is the most important factor in the regulation of muscle LDH isoenzyme distribution. On the other hand, muscle metabolism can also be regulated by axonally transported molecules.The results presented here show that there is a qualitative difference between the effects of denervation and those of axonal transport blockade upon the muscle, since only denervation altered the isoenzyme pattern of muscl

ISSN:0022-3034    

DOI:10.1002/neu.480150205

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

年代:1984

数据来源: WILEY

摘要:

AbstractA new learning paradigm which employs a natural aversive stimulus, tightly constrains learned behavior and demonstrates learning in individual animals is described. Locusts were restrained so that only the femoro‐tibial joint of a single metathoracic leg was free to move. Animals were required to maintain a particular range of femoro‐tibial joint angle to avoid heating of the head. The position of the tibia was sampled by an on‐line computer which set the limits of joint angle and controlled the aversive stimulus while storing data for further analysis. Control animals received patterns of aversive stimuli identical to those received by experimental animals but independent of their own joint position. Quantitative evaluation of the learned behavior of individual animals allowed the identification of three different behavioral strategies by which learning was ach

ISSN:0022-3034    

DOI:10.1002/neu.480150206

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe effects of the sodium ionophore monensin were examined in the bag cells ofAplysia californicain order to identify the subcellular sites of processing of precursors to their neurosecretory products. Incubation of bag cells in media containing 10 μMmonensin led to a marked disruption of the morphology of the Golgi apparatus without affecting that of other organelles. Exposure of bag cells to monensin led to a significant impairment of processing of the largest precursor and of an intermediate protein which gives rise to the immediate precursors to the final secreted products, the egg‐laying hormone (ELH) and the acidic peptide (AP). Furthermore, ELH and AP were never produced in the presence of monensin during the time course of these experiments. When axonal transport was allowed to proceed, the contents of bag‐cell terminals indicated that the intermediate protein is the first to be packaged in Golgi‐derived vesicles, and in monensin‐treated cells may be transported without being processed further. In contrast to these results, the protonophore FCCP‐impaired precursor and intermediate cleavage equally, indicating that monensin and FCCP have different effects on intracellular transport and precursor processing. These data are interpreted to indicate that the largest ELH‐AP precursor is normally processed within the Golgi apparatus, and that the disruption of this organelle induced by monensin produces the impairment seen in its processing. The impairment of cleavage of the intermediate species, and the blockade of production of AP and ELH, are probably the result of monensin‐induced impairment of production of proteolytically competent secretory granules by the G

ISSN:0022-3034    

DOI:10.1002/neu.480150207

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

年代:1984

数据来源: WILEY

摘要:

AbstractSustained contraction of the chick biventer cervicis nerve‐muscle preparations evoked by α‐latrotoxin was antagonized quickly by β‐bungarotoxin. This effect of β‐bungarotoxin was dependent on its phospholipase A2activity. In contrast, pancreatic phospholipase A2was ineffective even at a much higher dose. It is concluded that α‐latrotoxin needs intact presynaptic membrane to exe

ISSN:0022-3034    

DOI:10.1002/neu.480150208

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

年代:1984

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480150209

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

年代:1984

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480150210

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

年代:1984

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480150211

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

年代:1984

数据来源: WILEY