51
|
Berdan RC, Bulloch AG. Role of activity in the selection of new electrical synapses between adult Helisoma neurons. Brain Res 1990; 537:241-50. [PMID: 2085776 DOI: 10.1016/0006-8993(90)90364-h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Our aim was to determine whether neural activity in the form of sodium-dependent action potentials play a role in the formation, maintenance and specificity of electrical synapses between regenerating neurons. We axotomized buccal neurons of the mollusc, Helisoma trivolvis, and placed ganglia into organ culture in the absence or presence of tetrodotoxin (TTX), a specific sodium channel blocker. Electrical coupling was measured using intracellular microelectrodes positioned within the soma of identified neurons. Neurite outgrowth was assessed by epifluorescence microscopy after filling neurons by iontophoresis with Lucifer yellow. Previous studies found that two days after axotomy transient electrical synapses form between heterologous neurons (e.g. buccal neurons 4 and 5). Five days after axotomy these transient connections disappeared and a new electrical synapse was stabilized between the paired buccal neurons 5. To determine whether blocking neural activity with TTX affected the specificity and formation of new electrical synapses, we examined electrical coupling between the heterologous neurons 4 and 5 two days after axotomy, and the paired buccal neurons 5 five days after axotomy. Our electrophysiological recordings indicated that different neurons in the buccal ganglion varied in their sensitivity to TTX (i.e. sensitivity of buccal neurons 19 greater than 5 greater than 4), but spontaneous activity was abolished in all 3 neurons by 2 x 10(-5) M TTX. Furthermore, the inhibitory effects of TTX occurred within seconds of superfusion and persisted for at least 6 days. Inhibition of activity by TTX could be reversed after superfusion with normal saline. Neurite outgrowth from axotomized neurons was not appreciably altered in the presence of TTX. Furthermore, no differences in the incidence of electrical coupling or the coupling resistance were detected between neurons 4 and 5 two days after axotomy and organ culture in the presence of TTX. However, electrical coupling between the symmetrically paired neurons 5 was elevated in the presence of TTX after 5 days. We conclude from these results that neural activity in the form of sodium-dependent action potentials does not play an important role in the formation or breaking of transient electrical synapses during neuronal regeneration in the mollusc Helisoma trivolvis.
Collapse
|
52
|
Montemayor ME, Fahrbach SE, Giometti CS, Roy EJ. Characterization of a protein that appears in the nervous system of the moth Manduca sexta coincident with neuronal death. FEBS Lett 1990; 276:219-22. [PMID: 2265704 DOI: 10.1016/0014-5793(90)80546-u] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Two-dimensional gel electrophoresis was used to locate potential neuronal death-related proteins in the moth Manduca sexta. Protein patterns of ganglia of pharate adult moths (taken prior to adult ecdysis) compared with protein patterns of one-day-old adults revealed reproducible changes in protein patterns. An acidic protein of approximately 40,000 Da was present in all samples from adult moths undergoing neuronal death and essentially absent from pharate adult samples.
Collapse
|
53
|
Katz DM, Erb MJ. Developmental regulation of tyrosine hydroxylase expression in primary sensory neurons of the rat. Dev Biol 1990; 137:233-42. [PMID: 1968026 DOI: 10.1016/0012-1606(90)90250-m] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The regulation of transmitter phenotype in primary sensory neurons remains poorly understood. However, recent studies of catecholaminergic (CA) sensory neurons suggest that expression of this particular phenotype may be related to innervation of specific peripheral tissues. In the glossopharyngeal petrosal ganglion (PG) of adult rats, for example, the vast majority of CA sensory neurons innervate a single target, the carotid body. The present study was undertaken, therefore, to begin investigating factors that underlie CA differentiation in sensory neurons, using the rat PG as a model system. Immunocytochemical, biochemical, and morphometric methods were used to investigate the normal time course of CA development in the PG in vivo, employing tyrosine hydroxylase (TH) as a phenotypic marker. These studies revealed two temporally distinct waves of TH expression during embryogenesis. TH immunoreactivity was initially detectable on Embryonic Day (E) 11.5; the number of stained cells increased markedly by E12.5 and then fell off sharply to near 0 by E15.5. Simultaneous immunostaining for TH and neurofilament proteins revealed a high proportion of double-labeled perikarya on E12.5, indicating that the transiently TH-positive cells are neurons. A second, sustained phase of TH expression began on E16.5, and by Postnatal Day 1 adult numbers of TH-containing ganglion cells were present. Western blot analysis demonstrated that TH levels per cell rose 3.5-fold in the perinatal period, indicating that maturation of this particular catecholaminergic trait in PG sensory neurons is highly regulated around birth. Morphometric techniques were used to define the relationship between neurons that transiently exhibit TH immunoreactivity early in gangliogenesis and those that maintain enzyme expression in the mature PG. These studies revealed separate and distinct growth curves for the early and late TH cells, respectively, demonstrating that the appearance, disappearance, and reappearance of immunoreactive cells reflects the differentiation of two separate populations of PG neurons. Moreover, these data indicate that TH expression in the population of CA cells that persists in the mature PG begins around E16.5. This is after peripheral target innervation has begun, raising the possibility that neuron-target interactions regulate biochemical differentiation of these CA sensory neurons.
Collapse
|
54
|
Abstract
During ontogenetic development in the definitive host, the cerebral ganglia of the parasitic flatworm Fasciola hepatica lose their cell rind integrity and develop specialized nerve processes. The organization and cytological features of the central nervous system were examined during three developmental stages in the parasitic life cycle of F. hepatica to determine when the changes occur. The cerebral ganglion cell bodies of migrating juvenile worms (5 days post-infection) are organized into a one-cell-thick rind that surrounds a central neuropile composed of small unmyelinated nerve processes (less than 3 microns in diameter). In young, sexually-immature adult worms (30 days post-infection), the cell bodies of the ganglia are no longer organized into a complete or tight cell rind around the ganglia. In addition, large diameter ('giant') unmyelinated nerve processes (greater than 12 microns) are found in the neuropile area. These giant nerve processes are also found in the transverse commissure and the longitudinal nerve cords. In mature adult worms (4-6 months post-infection), the rind of nerve cell bodies has completely disappeared and cell bodies are scattered around and within the neuropile. More than half of the volume of the mature adult neuropile is composed of giant nerve processes. The three developmental stages of the parasite that were used in this study differ significantly in their sizes, behaviours and microhabitat locations in the host. The results suggest that the organizational and morphological changes in the ganglia reflect selective adaptations to changes in the parasitic microenvironment.
Collapse
|
55
|
Breidbach O. Fate of descending interneurons in the metamorphosing brain of an insect, the beetle Tenebrio molitor L. J Comp Neurol 1989; 290:289-309. [PMID: 2592614 DOI: 10.1002/cne.902900209] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The fate of descending brain-thoracic neurons in the metamorphosing supraoesophageal ganglion of the mealworm beetle, Tenebrio molitor, is described. Comparison of the descending neurons of the larval, various pupal, and adult stages outlines a high degree of topological invariance in the structure of descending interneurons; i.e., the basic organization of the imaginal set of descending neurons is anticipated by the structure of the larval neurons. Single descending neurons of analogous clusters of larval and imaginal neurons outline a virtual identical structural organization in both the larval and imaginal brain. There is a quantitative increase from approximately 70 to approximately 120 brain-thoracic interneurons during metamorphosis. This increase does not cause complex transformations in the structural organization of the descending interneurons. Experiments with the DNA-inhibitor hydroxyurea prove that the described topological invariant structure of the set of descending neurons is based on the persistence of individually descending neurons. There is evidence that the whole set of larval interneurons persists throughout the beetles' metamorphosis. The essential characteristics of the later imaginal set of descending neurons are qualitatively and quantitatively established within the first 10% of pupation. Structural invariance of the set of descending neurons is discussed with regard to the significance of cellular interaction for the mechanisms of metamorphic reorganization of nervous tissue.
Collapse
|
56
|
Goldberg JI, Kater SB. Expression and function of the neurotransmitter serotonin during development of the Helisoma nervous system. Dev Biol 1989; 131:483-95. [PMID: 2912804 DOI: 10.1016/s0012-1606(89)80019-3] [Citation(s) in RCA: 119] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Exogenous serotonin has been shown to evoke a neuron-selective inhibition of neurite outgrowth and synaptogenesis in identified Helisoma neurons in vitro. We demonstrate here that serotonin is present in the embryonic nervous system of Helisoma and can act as a regulator of neuronal development in vivo. Serotonin-like immunoreactivity was first observed in neurons at an early stage of nervous system development (E20). Throughout embryogenesis, the number of serotonin-immunoreactive neurons increased in a stereotypic pattern that was unique for each type of ganglion. Strikingly, the number of serotonin-immunoreactive neurons continued to increase throughout adult life. Transient perturbation of endogenous serotonin levels during embryogenesis had profound effects on the development of specific identified neurons. Embryos treated with 5,7-dihydroxytryptamine and raised to maturity showed aberrations in neuronal morphology, neuronal dye coupling, and strength of electrical synaptic connections. These effects were restricted to neurons known to be sensitive to the growth-inhibitory effects of serotonin in vitro. These results support the hypothesis that neurotransmitters are an important class of regulatory factors during normal development of the nervous system.
Collapse
|
57
|
Croll RP, Chiasson BJ. Postembryonic development of serotoninlike immunoreactivity in the central nervous system of the snail, Lymnaea stagnalis. J Comp Neurol 1989; 280:122-42. [PMID: 2918092 DOI: 10.1002/cne.902800109] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Posthatching growth in the pond snail Lymnaea stagnalis involves approximately a 20-fold increase in the linear dimensions of the ganglia composing the central nervous system. Developmental change within the population of neurons exhibiting serotoninlike immunoreactivity (SLIR) was examined in order to explain this growth in cellular terms. The study indicates that at least two factors contribute to the growth of the nervous system. First, SLIR cells approximately double in number from the 200-250 cells in hatchlings to the complement found in animals approaching sexual maturity. Much of this increase in cell number occurred within identifiable discrete clusters of neurons with different clusters adding cells at different rates and at different times. The number of SLIR cells also increased in more diffuse populations, particularly along the medial aspects of the paired pedal and the right parietal ganglion. No identified cells were added postembryonically. In addition to the increases in neuron numbers, posthatching development in Lymnaea also involves the growth of individual cells. All cells examined showed continuous somatic growth during posthatching development, but different identified cells and different cell clusters were characterized by different rates of relative growth. Together, the results highlight the complexity of postembryonic development in the snail by indicating the temporal and spatial specificity for both cell addition and cell growth within the nervous system.
Collapse
|
58
|
Melvin JE, Hamill RW. Androgen-specific critical periods for the organization of the major pelvic ganglion. J Neurosci 1989; 9:736-42. [PMID: 2918385 PMCID: PMC6569793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Previous studies indicate that the major pelvic ganglion (PG) is dependent on testosterone for normal development. Tyrosine hydroxylase (T-OH), DOPA decarboxylase, and choline acetyltransferase (CAT) activities are significantly reduced by postnatal castration on day 10-11, while testosterone replacement therapy reversed all developmental enzyme activity deficits (Melvin and Hamill, 1987). In the present studies castration on the day of birth combined with various testosterone-replacement paradigms produced effects demonstrating that the PG is sensitive to testosterone dosage and time of administration during early postnatal development. Gonadal hormone replacement experiments show that the androgens testosterone and dihydrotestosterone were effective in restoring T-OH and CAT activity deficits produced by neonatal castration. Estrogen therapy reversed the deficits in CAT activity, but was ineffective in reversing the alterations in T-OH activity. Treatment of pregnant dams with the anti-androgen flutamide altered the ontogeny of T-OH and CAT activities in pups despite replacement therapy on the day of birth. Thus, androgen-critical periods exist prenatally as well as postnatally. These studies suggest that the organization of PG development is critically dependent on both the time of exposure and dose of testosterone. Prenatal and postnatal critical periods appear to exist. In addition, the lack of an effect of estradiol on tyrosine hydroxylase activity suggests that androgens are specifically responsible for organizing the noradrenergic development of the PG.
Collapse
|
59
|
Cash D, Carew TJ. A quantitative analysis of the development of the central nervous system in juvenile Aplysia californica. JOURNAL OF NEUROBIOLOGY 1989; 20:25-47. [PMID: 2921607 DOI: 10.1002/neu.480200104] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The marine mollusc Aplysia californica has proved to be a useful preparation for analyzing the development of learning and memory on both behavioral and cellular levels. An important issue in this analysis concerns the anatomical substrate upon which learning is superimposed during development. As a first step in examining this question, in the present study we have determined the number of neurons in all the major central ganglia at each stage during juvenile development, a time when several forms of learning first emerge in Aplysia. We found that a large and highly nonlinear proliferation of neurons occurs during juvenile development, with the greatest increase in cell number occurring during a specific juvenile stage: Stage 12. The neuronal proliferation is system-wide, occurring in each of the central ganglia simultaneously, suggesting the action of a general developmental signal or trigger (perhaps a hormone). Accompanying the increase in neuron number in Stage 12 there is a large increase in neuropilar volume (150-fold), which significantly increases the opportunity for synaptic interactions late in juvenile development.
Collapse
|
60
|
Richard DS, Applebaum SW, Gilbert LI. Developmental regulation of juvenile hormone biosynthesis by the ring gland of Drosophila melanogaster. J Comp Physiol B 1989; 159:383-7. [PMID: 2509524 DOI: 10.1007/bf00692410] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The synthesis in vitro of the putative dipteran juvenile hormone (JHB3) by ring glands isolated from third instar Drosophila melanogaster larvae was quantified by a radiochemical assay. The data indicate that JHB3 synthesis is developmentally regulated during the period prior to wandering until after puparium formation. The highest level of basal production occurred during the postfeeding stage, and synthesis declined after pupariation. Similar relative profiles of synthesis were obtained upon the addition of the JHB3 precursor, farnesoic acid, although the absolute levels of production were elevated considerably. Basal JHB3 production by brain-ring gland complexes in vitro was also highest during the postfeeding stage, although the synthetic rates were much lower than displayed by isolated ring glands. Further analysis revealed that methyl farnesoate, a JHB3 precursor, was synthesized by brain-ring gland complexes in significant quantity. A dual mechanism of brain-centered control of JHB3 biosynthesis is proposed.
Collapse
|
61
|
Sato T, Ebisawa S, Wake K. Neuronal degeneration in the pineal ganglion during the post-hatching development of the domestic fowl. Cell Tissue Res 1988; 254:25-30. [PMID: 3197082 DOI: 10.1007/bf00220013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The frequency of pineal ganglia associated with the pineal tract, and the numbers of acetylcholinesterase-positive neurons in these ganglia were studied in the domestic fowl during the post-hatching period by means of the acetylcholinesterase method. Furthermore, the degeneration of nerve cells in pineal ganglia of 40-day-old domestic fowl was investigated in detail at the electron-microscopic level. The rate of pineal organs containing one or more ganglia was 50% in 2- to 13-day-old, 38% in 40-day-old, and only 10% in 1-year-old domestic fowl. In parallel, the number of acetylcholinesterase-reactive nerve cells that constitute individual pineal ganglia decreased after hatching. Various degrees of neuronal degeneration were found in the pineal ganglia: swelling of the endoplasmic reticulum, electron-dense degeneration of the cytoplasm, and pyknosis of the nerve cell nucleus. Clusters of macrophages containing numerous lysosomes filled with debris-like material were scattered in the ganglion. In addition, plasma cells were observed in association with degenerating nerve cells. These results confirm the suggestion that the loss of acetylcholinesterase-positive nerve cells in the pineal ganglia of the domestic fowl is due to naturally occurring, programmed neuronal cell death. This process is discussed with reference to phenomena of cell death observed in other components of central nervous system.
Collapse
|
62
|
Guillery RW, Jeffery G, Cattanach BM. Abnormally high variability in the uncrossed retinofugal pathway of mice with albino mosaicism. Development 1987; 101:857-67. [PMID: 3503699 DOI: 10.1242/dev.101.4.857] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Female mice showing albino mosaicism due to an X-autosome translocation [Is(In7;X)Ct] have been studied in order to investigate the relationship between the distribution of melanin and the formation, early in development, of the abnormally small uncrossed retinofugal pathway characteristically found in all albino mammals. Earlier evidence indicates that cells normally bearing melanin play a role in producing the abnormality. In the mosaic mice, the albino gene is expressed in only about half of the cells due to random X-inactivation and the patches of normal and albino cells are extremely small relative to total retinal size (less than 1/50). We argued that if all the cells that would normally bear melanin play a role in producing the albino abnormality then the mosaic mice would have a pathway abnormality, about half the size of that in the albino mice. If, however, only a small patch of these cells plays a role, as has been proposed in earlier studies, then one would expect the size of the uncrossed pathway to be highly variable in the mosaic mice. The size of the uncrossed pathway was assessed by placing horseradish peroxidase in the region of the optic tract and lateral geniculate nucleus unilaterally and then counting the number of retrogradely labelled retinal ganglion cells on the same side. The mosaic mice showed a highly variable uncrossed pathway. In some of the mosaic mice, it was the same size as in the albinos and, in others, it was the same size as in normally pigmented mice. Surprisingly, in a small number of mosaic mice, the uncrossed pathway was larger than normal. Whether this relatively rare occurrence of a supernormal uncrossed pathway is due to the higher gene dosage or to the translocation itself remains an open question.
Collapse
|
63
|
Melvin JE, Hamill RW. The major pelvic ganglion: androgen control of postnatal development. J Neurosci 1987; 7:1607-12. [PMID: 3598637 PMCID: PMC6568880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Previously we reported the effects of postnatal castration on the postorganizational development of the sympathetic hypogastric ganglion (Hamill and Guernsey, 1983; Melvin and Hamill, 1986). "Postorganization" implies an activational role for gonadal hormones, in contrast to the permanent organizing effects that occur perinatally. We now report results that suggest that the major pelvic ganglion (PG), a mixed parasympathetic and sympathetic ganglion, is similarly regulated by testosterone during development. Choline acetyltransferase (CAT) and tyrosine hydroxylase (T-OH) activities were used to examine normal PG ontogeny. The normal development of these biochemical indices occurs primarily after day 10. Postnatal castration at 10-11 d of age completely prevented the postorganizational developmental increase of T-OH activity. At 12 postoperative weeks T-OH activity in castrates was approximately 6% that of the control animals (control, 2880 +/- 127 pmol/ganglion X hr; castrated, 161 +/- 16 pmol/ganglion X hr; p less than 0.001). In fact, by only 1 postoperative week, T-OH activity was already significantly reduced in castrated animals (control, 480 +/- 69 pmol/ganglion X hr; castrated, 179 +/- 6 pmol/ganglion X hr; p less than 0.001). CAT activity and total ganglion protein were also significantly reduced by 1 postoperative week. In contrast to T-OH activity, however, these indices continued to develop at diminished rates. By 12 postoperative weeks CAT activity and total ganglion protein in castrates were 30 and 50% of control values, respectively, resulting in a significant developmental abnormality in CAT-specific activity. Testosterone replacement reversed the castration-induced developmental deficits of T-OH and CAT activities.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
64
|
Raivich G, Zimmermann A, Sutter A. Nerve growth factor (NGF) receptor expression in chicken cranial development. J Comp Neurol 1987; 256:229-45. [PMID: 3031137 DOI: 10.1002/cne.902560204] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In order to map the expression of receptors for nerve growth factor (NGF) during brain and cranial ganglia development, iodinated NGF (125I beta NGF) was used as a probe in an autoradiographical analysis performed between embryonic day 3 (E3) and posthatching day 3 (P3) of chicken development. Heavy autoradiographic labelling was observed at the classical NGF target sites, the proximal cranial sensory ganglia and the sympathetic superior cervical ganglion, throughout development and after hatching. In contrast, only weak labelling could be detected during a restricted time span in the vestibulocochlear (E4-E8) and the distal cranial sensory ganglia (E4-E10), the neurons of which originate from the otic and epibranchial placodes. Specific 125I beta NGF binding was also observed in various brain regions during early brain development. NGF receptor expression there followed a characteristic pattern. The neuroepithelial layer displayed very low levels of specific 125I beta NGF binding, while strong 125I beta NGF labelling was found in the mantle layer. Brainstem somatomotor nuclei, visceromotor columns, brainstem alar plate, cerebellar anlage, tectum, and basal forebrain (epithalamus, striatum) were found to be transiently labelled by 125I beta NGF in early development (E4-E12). Non-nervous tissues such as parts of the otic vesicle epithelium and skeletal muscle anlagen of the head were also labelled. These results, showing specific binding of 125I beta NGF to cranial cells of different origin (neural tube, neural crest, placode, and possibly mesoderm) strengthen the concept that NGF may have diverse functions in growth and differentiation of various tissues and cell types.
Collapse
|
65
|
Nässel DR, Ohlsson L, Sivasubramanian P. Postembryonic differentiation of serotonin-immunoreactive neurons in fleshfly optic lobes developing in situ or cultured in vivo without eye discs. J Comp Neurol 1987; 255:327-40. [PMID: 3546409 DOI: 10.1002/cne.902550302] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The differentiation of serotonin-immunoreactive (5-HTi) neurons in the optic lobes of fleshflies was studied during in situ development and in in vivo cultures. All 5-HTi neurons with cell bodies in the imaginal optic lobes differentiate during postembryonic (pupal) development. These are local anaxonal neurons. In addition there are two large 5-HTi bilateral neurons that connect all optic lobe neuropil regions on both sides of the brain and have their cell bodies in the midbrain proper. Deafferentation of optic lobes cultured in vivo leads to drastic reduction in optic lobe volume and increased cell death. All the 5-HTi neurons differentiate after deafferentation but their morphology changes. The neuropil receiving the photoreceptor inputs, the lamina, degenerates but a disorganized "pseudolamina" is formed by the processes of the two large 5-HTi neurons. The layering of the optic lobe neuropils cannot be distinguished and 5-HTi processes form novel projectional patterns. Hence, the 5-HTi neurons do not require afferent inputs from the retina for their differentiation and survival, but the effect on other optic lobe interneurons is reflected in the morphological plasticity of the 5-HTi neurons.
Collapse
|
66
|
Oland LA, Tolbert LP. Glial patterns during early development of antennal lobes of Manduca sexta: a comparison between normal lobes and lobes deprived of antennal axons. J Comp Neurol 1987; 255:196-207. [PMID: 3819014 DOI: 10.1002/cne.902550204] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The synaptic neuropil of the olfactory (antennal) lobe of the moth Manduca sexta is subdivided into histologically conspicuous structures called glomeruli that are typical of olfactory systems in vertebrates and invertebrates. Each glomerulus consists of the highly branched neuritic arbors of both primary olfactory axons and antennal-lobe neurons, bounded by a nearly complete envelope of glial cells. We have studied events occurring during the first half of metamorphic adult development. The first signs of organization of the neuropil into glomeruli are changes in glial cells. Prior to the ingrowth of olfactory axons from the antenna, glial cells form a continuous border around the neuropil. When olfactory axons begin to reach the lobe, glial cells embark on a stereotyped series of changes: the border becomes disrupted, glial cells begin to proliferate and extend processes into the outer regions of the neuropil, and some glial cells migrate toward the center of the neuropil. Shortly thereafter, glomeruli emerge from the neuropil, delineated by glial cells. If, however, afferent axons are prevented from ever reaching the antennal lobe, glomeruli never develop and the glial cells remain almost entirely restricted to a thick layer bordering the neuropil. Thus sensory axons have a direct influence not only on neuronal but also on glial differentiation. Our results lead us to suggest that the glial cells may be in a position to act as intermediaries in developmental interactions between sensory axons and antennal-lobe neurons.
Collapse
|
67
|
Shishov BA, Liukshina LM, Shcherbakova MA. [Constancy and variability of aminergic nerve cells at different stages of the life cycle of the parasitic trematode Fasciola hepatica]. ZHURNAL OBSHCHEI BIOLOGII 1987; 48:124-35. [PMID: 3564698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
68
|
|
69
|
Stewart RR, Spergel D, Macagno ER. Segmental differentiation in the leech nervous system: the genesis of cell number in the segmental ganglia of Haemopis marmorata. J Comp Neurol 1986; 253:253-9. [PMID: 3793993 DOI: 10.1002/cne.902530211] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In hirudinid leeches, the segmental ganglia associated with the sexual organs contain several hundred more neurons than other midbody ganglia. To determine whether this difference arises by differential cell addition or by differential cell death, cell counts were made in several segmental ganglia during the course of embryonic and postembryonic development. The results show that all ganglia behave equally in early development. In each case, at least 10-20% more cells than will make up the adult complement of about 400 neurons is generated, and by about 20 days of embryonic development cell loss brings the number down to about 400 cells. By about 30 days, when animals emerge from their cocoons, additional cells have begun to appear in the sex ganglia. The number of extra cells continue to increase gradually over the next several months, until the adult number of 600-700 neurons is attained. These observations indicate that at least some segmental differences in the size of neuronal populations are due to differential cell proliferation and that these differences can arise quite late in the maturation of an animal.
Collapse
|
70
|
Copenhaver PF, Truman JW. Metamorphosis of the cerebral neuroendocrine system in the moth Manduca sexta. J Comp Neurol 1986; 249:186-204. [PMID: 3734157 DOI: 10.1002/cne.902490206] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We have examined the morphology and neuronal elements of the cerebral neuroendocrine system in the larval, pupal, and adult stages of the moth Manduca sexta with a variety of neuroanatomical techniques. The larval brain contains several discrete groups of neurosecretory and non-neurosecretory cells that project to the associated neurohemal organs (the corpora cardiaca-allata complex, or CC-CA) and to a variety of more peripheral structures. A previously undescribed set of cells in the subesophageal ganglion have also been found that project out the neurosecretory nerves. During metamorphosis, the cerebral neuroendocrine system undergoes a dramatic structural reorganization, including the reduction or loss of many larval nerves and a repositioning of the cell groups and their dendritic fields. Despite these changes, most of its central elements are retained. In addition, by the completion of adult development a new cluster of cells can be found on either side of the dorsal midline of the brain. We have also determined the relative contributions of the different cell groups to the moth neuroendocrine system by intracellular iontophoresis of dye into individual cells. Within the dorsal protocerebrum, five separate morphological types of cells can be recognized, each with a distinctive pattern of dendritic arborization in the brain and terminal neurohemal processes that project to the CC, the CA, the aorta, or to a combination of these regions. The large intrinsic cells of the CC have also been filled, revealing an unusual set of morphological features in these peripheral neurosecretory cells.
Collapse
|
71
|
White K, Hurteau T, Punsal P. Neuropeptide-FMRFamide-like immunoreactivity in Drosophila: development and distribution. J Comp Neurol 1986; 247:430-8. [PMID: 3088066 DOI: 10.1002/cne.902470403] [Citation(s) in RCA: 137] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Neuropeptide-FMRFamide-like immunoreactivity was characterized in the fruit fly, Drosophila melanogaster. In the adult central nervous system, a stereotypic pattern of immunoreactive cell bodies and immunoreactive nerve processes and varicosities was observed, indicating a neurochemical role for FMRFamide-like substance(s) in Drosophila. Localization of immunoreactivity in the central nervous system of early larval stage revealed that the majority of the prominent FMRFamide-like immunoreactive neurons were already differentiated. The FMRFamide-like immunoreactive neurons remain immunoreactive throughout postembryonic stage and persist in the adult central nervous system. In the larva, in addition to the central nervous system, FMRFamide-like immunoreactivity was localized in the fibers innervating the ring gland, in the ganglion innervating the gut and in the gastric caeca.
Collapse
|
72
|
Lester DS, Gilbert LI. Developmental changes in choline uptake and acetylcholine metabolism in the larval brain of the tobacco hornworm, Manduca sexta. Brain Res 1986; 391:201-9. [PMID: 3697775 DOI: 10.1016/0165-3806(86)90284-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The larval brain of the tobacco hornworm, Manduca sexta, was maintained in vitro and the uptake of labelled and unlabelled choline as well as their subsequent metabolism were measured by high-voltage paper electrophoresis. Significant levels of choline lipid metabolites, phosphorylcholine and acetylcholine (ACh) were noted. Unbound choline reached equilibrium after 6-8 h of incubation, while ACh accumulation continued to increase after 24 h indicating that the rate of synthesis exceeded the rate of breakdown. An apparent Km could not be determined for these whole-organ studies; however, the Vmax for ACh accumulation for days 5 (70 pmol/brain/h) and 6 (105 pmol/brain/h) of the last larval instar did vary significantly while the level of unbound choline in the brain did not change. The level of choline uptake was dependent upon the presence of Na+ and Ca2+, while the amount of ACh accumulated was affected specifically by the presence of Mg2+, the latter ion activating acetylcholinesterase. The determination of levels of unbound choline and ACh accumulation in the developing brain during the last two larval instars demonstrated increases in acetylcholine accumulation at previously reported times of the release of the hormone that initiates the molting process, prothoracicotropic hormone. These changes in the patterns of ACh accumulation occur during 4-8 h time intervals; this is the first report of such short-range changes in neurotransmitter metabolism in whole brains. The intensity of the ACh accumulation shift is equivalent to the intensity of the hormone burst. Other fluctuations in the levels of ACh accumulation and free choline correlate with the development of the brain.
Collapse
|
73
|
Abstract
The peripheral nervous system of vertebrates arises from the neural crest and the ectodermal placodes. Construction of quail-chick chimaeras has provided significant information on the migration and fate of the neural crest and placodal cells. Transplantation of neural crest tissue to various sites in these chimaeras has demonstrated that the differentiation of neural crest cells is controlled by environmental influences during their migration and, particularly, during gangliogenesis. Experiments with in vitro and monoclonal antibody techniques have shown that these environmental cues act on a heterogeneous population of neural crest cells whose developmental potencies are partly restricted to definite differentiation pathways.
Collapse
|
74
|
Johansen J, Thompson I, Stewart RR, McKay RD. Expression of surface antigens recognized by the monoclonal antibody lan 3-2 during embryonic development in the leech. Brain Res 1985; 343:1-7. [PMID: 2412641 DOI: 10.1016/0006-8993(85)91151-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The monoclonal antibody lan 3-2 was used as a marker for the developmental expression of surface antigens which are specific for the two pairs of nociceptive neurons and a subset of axons in the adult CNS of the leech. In Haemopis embryos labeling of both nerve fibers and cell bodies with the antibody appears as expected for a metameric animal in a rostrocaudal temporal gradient from about day 5-6. Surprisingly, all central cell bodies are stained by the antibody in early development. However, later in embryogenesis around day 17 the staining intensity of most cells decreases except for the nociceptive cells, which remain antibody-positive, and the adult staining pattern gradually emerges. In addition to describing the central staining pattern, we show that specific peripheral neurons associated with the segmental sensilla also are antibody-positive during development. The distribution and developmental expression of the lan 3-2-positive antigens are compared between two phylogenetically different species of leeches and the diversity of the staining pattern of the monoclonal antibody is discussed.
Collapse
|
75
|
Heathcote RD, Sargent PB. Loss of supernumerary axons during neuronal morphogenesis. J Neurosci 1985; 5:1940-6. [PMID: 4020426 PMCID: PMC6565111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The morphogenesis of individual neurons was investigated in the cardiac ganglion of the frog. Intracellular injection of horseradish peroxidase shows that mature neurons lack dendrites and have a single axon. Early in development, more than half of the neurons are multipolar and have as many as four processes emanating from their cell body. The most likely mechanism for the developmental transformation of larval neurons is that the supernumerary processes are pruned from the cell body. Supernumerary processes in larval neurons have features characteristic of axons. The processes of larval neurons can be highly branched and extend throughout the target with distinctive varicosities along the length of each process. Electron microscopy shows that all processes of individually injected cells contain clusters of vesicles apposed to active zones. Thus, the larval cardiac ganglion neuron is capable of extending more than one axon from its cell body.
Collapse
|