1
|
Abstract
Olfactory nerve axons terminate in rounded regions of the olfactory bulb, termed glomeruli, where they make excitatory synapses with the dendrites of second-order neurons. Neurotransmission from the olfactory nerve to the postsynaptic targets is negatively regulated by gamma-aminobutyric acid (GABA), and there is evidence that inhibition of sensory input is mediated, at least in part, by GABA(B) receptors. Using an antiserum that recognizes two GABA(B) receptor splice variants (GBR1a and GBR1b), we show here that GABA(B) receptors are located on the axon terminals of the olfactory nerve, where they are concentrated at sites of axodendritic apposition. Taken with previous data, these results indicate that GABA(B) receptors act presynaptically to regulate the release of glutamate from olfactory nerve terminals.
Collapse
Affiliation(s)
- M Bonino
- Department of Anatomy, Pharmacology and Forensic Medicine, Turin, Italy
| | | | | |
Collapse
|
2
|
Quaglino E, Giustetto M, Panzanelli P, Cantino D, Fasolo A, Sassoè-Pognetto M. Immunocytochemical localization of glutamate and gamma-aminobutyric acid in the accessory olfactory bulb of the rat. J Comp Neurol 1999; 408:61-72. [PMID: 10331580 DOI: 10.1002/(sici)1096-9861(19990524)408:1<61::aid-cne5>3.0.co;2-f] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The synaptic organization of the accessory olfactory bulb (AOB) was studied in the rat with antibodies against the excitatory neurotransmitter glutamate (Glu) and the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). To a large extent, the immunoreactivity patterns produced by the two antibodies were complementary. Glu-like immunoreactivity (-LI) was observed in the glomerular neuropil, in the mitral cells, and in large neurons located in the periglomerular region. Immunogold electron microscopy revealed particularly high levels of Glu-LI in the axon terminals of vomeronasal neurons. GABA-LI was present in granule and periglomerular cells and in their processes. The dendritic spines of granule cells, which were presynaptic to mitral cells, were strongly labelled by the antiserum against GABA. Labelling of serial semithin sections showed that the GABA-positive and Glu-positive neurons of the periglomerular region are generally distinct, and colocalization of Glu and GABA occurred only in a few cells. These results are consistent with electrophysiological studies indicating that the synaptic organization of the AOB is similar to that of the main olfactory bulb. In both systems, Glu is the neurotransmitter used by primary afferents and output neurons, whereas GABA is involved in the circuits underlying lateral and feed-back inhibition.
Collapse
Affiliation(s)
- E Quaglino
- Dipartimento di Anatomia, Farmacologia e Medicina Legale, Universitá di Torino, Italia
| | | | | | | | | | | |
Collapse
|
3
|
Affiliation(s)
- M Sassoè-Pognetto
- Department of Anatomy, Pharmacology and Forensic Medicine, University of Turin, Italy.
| | | | | | | | | | | |
Collapse
|
4
|
Abstract
The tubulin-binding protein gephyrin is essential for the formation of postsynaptic glycine-receptor clusters in cultured spinal neurons. In addition, there is increasing evidence that gephyrin can also be present at nonglycinergic synapses. Here we analyzed immunocytochemically the subcellular localization of gephyrin in the main olfactory bulb of the rat and compared its distribution with that of gamma-aminobutyric acid (GABA) and of two major GABA(A)-receptor subunits. Gephyrin was selectively localized to the postsynaptic side of symmetric synaptic junctions, where the presynaptic terminals contained GABA. Moreover, gephyrin colocalized extensively with the alpha1 and gamma2 subunits of the GABA(A) receptor. In contrast, gephyrin was not detected at presumed glutamatergic synapses. These results indicate that gephyrin is not uniquely associated with glycine receptors, but can also be found at distinct GABAergic synapses. Thus, they raise the possibility that gephyrin is involved in anchoring certain GABA(A)-receptor subtypes in the postsynaptic membrane.
Collapse
Affiliation(s)
- M Giustetto
- Dipartimento di Anatomia, Farmacologia e Medicina Legale, Università di Torino, Italy
| | | | | | | | | |
Collapse
|
5
|
Abstract
Immunocytochemical methods were used to visualize carnosine (beta-alanyl-L-histidine)-like immunoreactivity (-LI) in the frog retina and to compare its localization with that of glutamate. Carnosine-LI was conspicuous in photoreceptors and bipolar cells. The axon terminals of labelled bipolar cells formed five bands in the inner plexiform layer. A few presumed amacrine and ganglion cells, as well as Müller cell endfeet, were also labelled. Post-embedding immunocytochemistry revealed particularly high levels of glutamate-LI in the synaptic axon terminals of bipolar cells, with a mean gold particle density 5 x higher than that of amacrine cells. Photoreceptor terminals were also labelled, but with a labelling intensity about half that of bipolar cells. Labelling of serial semithin sections showed co-localization of carnosine and glutamate in photoreceptors and bipolar cells. These findings are consistent with the notion that glutamate is the neurotransmitter of neuronal elements that transfer information vertically through the retina. We propose that carnosine may modulate GABA and/or glutamate receptors by virtue of its ability to chelate Zn2+ and other ions.
Collapse
Affiliation(s)
- P Panzanelli
- Department of Anatomy, Pharmacology and Forensic Medicine, University of Turin, Italy
| | | | | |
Collapse
|
6
|
Giustetto M, Bovolin P, Fasolo A, Bonino M, Cantino D, Sassoe-Pognetto M. Glutamate receptors in the olfactory bulb synaptic circuitry: heterogeneity and synaptic localization of N-methyl-D-aspartate receptor subunit 1 and AMPA receptor subunit 1. Neuroscience 1997; 76:787-98. [PMID: 9135051 DOI: 10.1016/s0306-4522(96)00285-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this study, we analysed the molecular heterogeneity and synaptic localization of the N-methyl-D-aspartate receptor subunit 1 and the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor subunit 1 in the olfactory bulb glomerular synaptic circuitry. Semiquantitative reverse transcriptase polymerase chain reaction showed that approximately 40% of the N-methyl-D-aspartate receptor subunit 1 messenger RNA splice variants contain the N1 exon, which conveys specific functional properties on the channel. In other forebrain and hindbrain regions that we examined, the ratio of the N1-containing (receptor subunit 1(1XX)) to N1-lacking (receptor subunit 1(0XX)) N-methyl-D-aspartate receptor subunit 1 messenger RNAs varied considerably. The cellular and subcellular distribution of N-methyl-D-aspartate receptor subunit 1 and AMPA receptor subunit 1 was investigated with antibodies generated against the C-terminal domain of the individual subunits [Petralia R. S. et al. (1994) J. Neurosci. 14, 667 696; Wenthold R. J. et al. (1992) J. biol Chem. 267, 501 507]. Both N-methyl-D-aspartate receptor subunit 1 and AMPA receptor subunit 1 were localized to the postsynaptic density of asymmetric synapses established by olfactory receptor neuron terminals with the dendrites of mitral and tufted cells. Not all of these synapses, however, were labelled. These results are consistent with the notion that glutamate is the neurotransmitter at the olfactory nerve to mitral and tufted cell synapses, and suggest a high heterogeneity in the expression of the postsynaptic glutamate receptors.
Collapse
Affiliation(s)
- M Giustetto
- Department of Human Anatomy and Physiology, Corso Massimo d'Azeglio, Turin, Italy
| | | | | | | | | | | |
Collapse
|
7
|
Nico B, Cardelli P, Fiori A, Riccetelli L, Giglio RM, Strom R, Sassoé-Pognetto M, Cantino D, Bertossi M, Ribatti D, Roncali L. Developmental study of ultrastructural and biochemical changes in isolated chick brain microvessels. Microvasc Res 1997; 53:79-91. [PMID: 9056478 DOI: 10.1006/mvre.1996.1967] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The morphology of the endothelial junctions, the expression of the alkaline phosphatase (ALKP) and gamma-glutamyltranspeptidase (GGT) activities, and the transport systems for neutral amino acids (NAA) and for d-glucose were studied in parallel in isolated microvessels from the brains of 9-, 12-, and 21-day chick embryos and 30-day chickens using freeze-fracturing and biochemical techniques. In the 9-day embryos, the endothelium junctional plasma membranes show alignments of discrete intramembrane particles (Imps) on the replica P-faces. In the 12-day embryos, the junctional membranes show short fibrils of loosely interconnected fused Imps. In the 21-day embryos, the junction is characterized by simple networks, and in the 30-day chickens, by very dense meshworks of continuous, fibrillary strands. In early embryonic life, the ALKP activity is expressed at high levels, more markedly in the microvessels than in the whole brain. ALKP progressively declines in later embryos and even more in adulthood, when the activity is fivefold higher in the microvessels than in the whole brain. No GGT activity is expressed in either embryonic or adult microvessels. The transport systems for NAA and for d-glucose are most active in 12-day embryonic microvessels, and progressively less expressed by the 21st day and in the adult. The results taken as a whole suggest a close relationship between the morphological and the metabolic maturation of the endothelial barrier of cerebral vessels.
Collapse
Affiliation(s)
- B Nico
- Institute of Human Anatomy, Histology and Embryology, University of Bari Medical School, Bari, I-70124, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Cutrin JC, Cantino D, Biasi F, Chiarpotto E, Salizzoni M, Andorno E, Massano G, Lanfranco G, Rizzetto M, Boveris A, Poli G. Reperfusion damage to the bile canaliculi in transplanted human liver. Hepatology 1996; 24:1053-7. [PMID: 8903374 DOI: 10.1002/hep.510240512] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In 19 patients who have undergone orthotopic liver transplantation (OLT), the trend and degree of cholestasis was statistically monitored in terms of plasma levels of L-gamma-glutamyl transferase (GGT) and total bilirubin. In addition, the ultrastructure of the bile canaliculus was examined during the entire OLT procedure, i.e., during explantation, cold ischemia, and after 60 to 90 minutes of organ reperfusion. Cholestasis was evident from the second day after surgery, with a peak after approximately 10 to 16 days. Defined, small changes in the functional state of actin filaments were noted in the bile canalicular area after prolonged ischemia. But the morphological status of the bile canaliculi changed dramatically after reperfusion. In fact, the mean area and perimeter of the canaliculi had increased significantly, and there was a marked loss in the number of bile microvilli per unit of canalicular area. The bile canaliculus appears to be one of the liver structures most susceptible to ischemia-reperfusion damage. A series of biochemical changes occurring during ischemia and after reoxygenation of the transplanted liver, especially, would provide a reason for the observed early morphological damage of the bile canaliculus, which, in turn, would explain the cholestasis of these patients in the first posttransplantation period.
Collapse
Affiliation(s)
- J C Cutrin
- Department of Experimental Medicine and Oncology, University of Torino, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Abstract
We demonstrate that both glutamate-like and carnosine-like immunoreactivities are present in hair cells and in fibers of the vestibular organ of the frog inner ear. Comparison of the two immunoreactivity patterns indicates that glutamate and carnosine might be colocalized in some hair cells. The presence of glutamate-like immunoreactivity in hair cells is consistent with biochemical and pharmacological data indicating glutamate as the excitatory neurotransmitter in these sensory receptors. There is also evidence that carnosine might have a neuromodulatory function.
Collapse
Affiliation(s)
- P Panzanelli
- Department of Human Anatomy and Physiology, University of Turin, Italy
| | | | | | | |
Collapse
|
10
|
Nico B, Cantino D, Sassoé Pognetto M, Bertossi M, Ribatti D, Roncali L. Orthogonal arrays of particles (OAPs) in perivascular astrocytes and tight junctions in endothelial cells. A comparative study in developing and adult brain microvessels. J Submicrosc Cytol Pathol 1994; 26:103-9. [PMID: 8149327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The plasmamembranes of the astrocyte processes, which envelop the capillaries of the adult brain, contributing to the blood-brain barrier constitution, are characterized by peculiar aggregates of intramembrane particles (IMPs) packed in orthogonal arrays (orthogonal arrays of particles, OAPs). With the aim of investigating the maturation sequence of the cerebral microvasculature, the IMPs distribution has been analysed in the plasmamembranes of both perivascular astrocytes and endothelial cells of fractured microvessels, in 16-, 20-, 21-day chick embryo and 10-day chicken optic tecta. The IMPs distribution undergoes remarkable changes from late embryonic to early postnatal life in the astrocytes and endothelial cells as well. In the astrocyte plasmamembranes, short chains of individual particles and linear units of packed ones precede the appearance of complete OAPs; in the endothelium junctional plasmamembranes, fibrils of fused particles precede the formation of fibrillary networks which express the tight junction setting up. The parallel formation of the astrocytic OAPs and the endothelial tight junctions further supports the suggestion that mutual relationships establish between perivascular glia and endothelium in the cerebral microvasculature differentiation during the blood-brain barrier development.
Collapse
Affiliation(s)
- B Nico
- Institute of Human Anatomy, Histology and Embryology, University of Bari Medical School, Italy
| | | | | | | | | | | |
Collapse
|
11
|
Sassoè-Pognetto M, Cantino D, Panzanelli P, Verdun di Cantogno L, Giustetto M, Margolis FL, De Biasi S, Fasolo A. Presynaptic co-localization of carnosine and glutamate in olfactory neurones. Neuroreport 1993; 5:7-10. [PMID: 7904191 DOI: 10.1097/00001756-199310000-00001] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Olfaction plays a dominant role in modulating behaviour in most vertebrate species and the olfactory bulb is considered a model system for characterizing principles of neural computation. Nevertheless, although the physiology and neurochemistry of the olfactory circuits have been widely studied, the neurotransmitter released by olfactory receptor neurones remains unknown. We now describe the ultrastructural localization of the dipeptide carnosine and the excitatory amino acid glutamate in the glomerular layer of the mouse olfactory bulb. We demonstrate that both carnosine-like and glutamate-like immunoreactivities are selectively co-localized in the olfactory neurone boutons. These observations, taken with the recent findings of glutamate-receptor subunit expression in rodent olfactory bulb, argue compellingly for a role of glutamate in olfactory neurotransmission and suggest a modulatory effect of carnosine.
Collapse
Affiliation(s)
- M Sassoè-Pognetto
- Department of Human Anatomy and Physiology, University of Turin, Italy
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Pognetto MS, Panzanelli P, Fasolo A, Cantino D. Expression of carnosine-like immunoreactivity during retinal development in the clawed frog (Xenopus laevis). Brain Res Dev Brain Res 1992; 70:134-8. [PMID: 1473272 DOI: 10.1016/0165-3806(92)90111-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The development of neurons immunoreactive to carnosine (beta-alanyl-L-histidine) was studied in the retina of Xenopus laevis during the premetamorphic period. Carnosine-like immunoreactivity was detected in photoreceptors from stage 39/40 (according to Nieuwkoop and Faber [Normal Tables of Xenopus laevis (Daudin), Elsevier, Amsterdam, 1956]) and in bipolar cells and their processes in the inner plexiform layer from stage 44/45. At all the developmental stages studied, neuroepithelial cells at the ciliary margin were completely unstained, suggesting that carnosine is only present in postmitotic retinal neurons. This study demonstrates a correlation between the times of appearance of carnosine-like immunoreactivity during retinal development and the onset of visual function.
Collapse
Affiliation(s)
- M S Pognetto
- Dipartimento di Anatomia e Fisiologia Umana, Turin, Italy
| | | | | | | |
Collapse
|
13
|
Abstract
The distribution of carnosine-like immunoreactivity in photoreceptors of the frog retina was studied by post-embedding electron microscope immunocytochemistry. Different fixation and embedding procedures were applied and the best results were achieved on sections from tissue embedded in the hydrophilic resin LR White. All photoreceptor types present in the frog retina (red and green rods, single and double cones) were intensely reactive for the carnosine antiserum. The immunoreactivity was particularly prominent in the synaptic terminal, nucleus and myoid, but decreased in the ellipsoid and in the outer segment. Müller glial cells and horizontal and bipolar cell processes in the outer plexiform layer were completely unstained. At the level of the photoreceptor terminals, the presence of gold particles within the synaptic vesicles could be demonstrated. This study is the first to provide the anatomical evidence for the presence of carnosine in the synaptic vesicles of a nervous cell. The present data may be relevant to the understanding of the biological functions of carnosine (and related dipeptides) and offer an exploitable system in which to verify its proposed role as a neurotransmitter or neuromodulator in sensory systems.
Collapse
Affiliation(s)
- M S Pognetto
- Dipartimento di Anatomia e Fisiologia Umana, Turin, Italy
| | | | | |
Collapse
|
14
|
Nico B, Cantino D, Bertossi M, Ribatti D, Sassoé M, Roncali L. Tight endothelial junctions in the developing microvasculature: a thin section and freeze-fracture study in the chick embryo optic tectum. J Submicrosc Cytol Pathol 1992; 24:85-95. [PMID: 1617614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The development of the interendothelial tight junctions was studied in the microvessels of the otpic tectum of chick embryos, at the 14th-16th and 18th-20th incubation day (i.d.), and in post-hatching chickens, using thin sections and freeze-fracture techniques. At the 14th-16th i.d., the junctional plasmamembranes of the endothelial cells are simply apposed or fused for brief tracts showing a pentalaminar or trilaminar configuration. In the replicas the P-faces of the fractured junctional membranes are either lacking in intramembrane particles (IMPs) and characterized by finger-like depressions, or provided with discrete IMPs aligned in rows. At the 18th-20th i.d., the thin peripheral expansions of the endothelial cells are superimposed and welded by continuous pentalaminar junctions. Their fracture P-faces display junctional strands formed by parallel fibrils of fused IMPs, with or without interconnections. In the 10-day-old chickens the junctions consist of highly complex networks of fibrils. The results have made it possible to recognize precise relationships between the features of the developing endothelial junctions in the ultrathin sections and, respectively, in the replicas. Moreover, the observations suggest that tight junction formation occurs progressively in the cerebral microvessels by processes of alignment and fusion of the IMPs, which conclude with the arrangement of fibrils in networks.
Collapse
Affiliation(s)
- B Nico
- Institute of Human Anatomy, Histology and Embryology, University of Bari, Italy
| | | | | | | | | | | |
Collapse
|
15
|
Celio MR, Poncino A, Cantino D. [Presence of calretinin in neurons of the human intestine]. Boll Soc Ital Biol Sper 1992; 68:25-9. [PMID: 1503735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Calcium-binding proteins are present in different neuron populations in the Central Nervous System. As concerns the Enteric Nervous System, only a few studies have been performed. In the present work we investigated immunohistochemically the localization of Calretinin in neurons of the human intestinal wall. Our results showed the presence of stained cell bodies and fibers with antibodies against Calretinin in the Auerbach plexus. Since most of the enteric neurons are characterized by a slow phase after hyperpolarization caused by Ca2+ dependent K+ channels, the role of Calretinin could be to modulate this particular electrophysiological behaviour.
Collapse
Affiliation(s)
- M R Celio
- Institut Histologie et Embryologie-Université de Fribourg CH
| | | | | |
Collapse
|
16
|
Elia C, Bucca C, Rolla G, Scappaticci E, Cantino D. A freeze-fracture study of human bronchial epithelium in normal, bronchitic and asthmatic subjects. J Submicrosc Cytol Pathol 1988; 20:509-17. [PMID: 3179991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Tight junctions (TJ) play a major role in maintaining the integrity of epithelia. Damage of conducting airway surface epithelium is commonly observed in asthma, and recent data suggest that epithelial cells modulate airway smooth muscle tone by the production of relaxant factor(s). To evaluate the ultrastructure of tight junctions (TJ) in human bronchial epithelium of normal and diseased lung, biopsy samples were obtained by fiberoptic bronchoscopy in three normal healthy subjects, four asthmatic patients with bronchial hyperreactivity to methacholine and one heavy smoker with chronic bronchitis. Specimens were examined by electron microscopy, using both thin sections and freeze-fracture techniques. In normal subjects two types of TJ were identified, based on 27 type I, 23 type II junctional areas. Epithelium from the patient with chronic bronchitis showed extensive mucous metaplasia and only junctions of the second type. Extensive epithelial damage was detected in asthmatic subjects, so that a few TJ could be found. Varying degrees of TJ abnormalities were observed and the possible role of such ultrastructural derangements was discussed.
Collapse
Affiliation(s)
- C Elia
- Dipartimento di Anatomia e Fisiologia, Università di Torino, Italia
| | | | | | | | | |
Collapse
|
17
|
Abstract
We have examined the ultrastructural changes of axons and synaptic boutons in the intracerebellar nuclei of the rat at 3 days to one year after inferior olive lesion performed by means of electrocoagulation or 3-acetylpyridine injection. A large number of preterminal segments and axons terminals undergoes remarkable ultrastructural changes after total or subtotal olivary lesion. Large membrane bound vacuoles and clusters of small synaptic vesicles characterize a good number of these terminals at 3 days up to one month after the lesion. Tightly packed tubules and cisternae of smooth endoplasmic reticulum appear during the first week in an increasing number of axon terminals. Boutons with large whorled bodies formed by smooth membranes increase in number during the second half of the first month and further increase in density until the sixth month. They are still present in large amounts at one year. Immunoreactivity for 3',5'-guanosine-phosphate-dependent protein kinase, which is specific for Purkinje neurons, can be detected in the axons and synaptic terminals displaying the ultrastructural changes described above. These results are discussed in relation to a possible trophic action of the climbing fibers on the Purkinje cells. We suggest that, at least in part, these alterations may be the consequence of the intense Purkinje cell hyperactivity which is present for up to one month from inferior olive lesion.
Collapse
|
18
|
Cantino D, Marchiafava PL, Strettoi E, Strobbia E. Subsurface cisternae in retinal double cones. J Submicrosc Cytol 1986; 18:559-66. [PMID: 3746970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Double cones of tench and goldfish retina are characterized by extensive subsurface cisternae underlying the plasma membranes at the appositional area between the principal and accessory cone. Such a membrane system is absent in double cones of turtle and salamander retina. Measurements on both transverse and longitudinal sections gave a total appositional area of about 75 square microns, the subsurface cisterna in each element of the double cone being around 8-10% smaller due to multiple fenestrations at the level of the paraboloid. No gap junctions joining the inner segments of tench and goldfish double cones were detected, while gap junctions could be observed at the level of the ellipsoid and paraboloid of turtle double cones. The possible role of the subsurface cisternae in functional interactions between double cone elements is discussed.
Collapse
|
19
|
Cantino D, Barasa A, Guglielmone R. Catecholamine-containing neurons in Remak's ganglion: a developmental and tissue culture study. J Neurocytol 1982; 11:763-78. [PMID: 7143028 DOI: 10.1007/bf01153518] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Development and maturation of the catecholamine-containing neurons of the embryonic chick and quail Remak's ganglion were studied, using the glyoxylic acid method. Fluorescent neurons were detected in the pararectal segment of the ganglion from its earliest in vivo formation, and along the whole ganglionic chain in later developmental stages. In tissue culture, a large number of catecholamine-containing neurons matured in explants of both early and more developed ganglia, producing an extensive network of outgrowing fluorescent nerve processes. Pararectal ganglia, cultured in vitro for up to 4 days, gave rise, whatever the developmental stage examined, to fluorescent migratory neurons distributed either in ganglion-like clusters or singly in a large area surrounding the explant. Many non-fluorescent neurons were intermingled with the fluorescent ones in the explants, as well as in the outgrowth. Ganglia from segments adjacent to the small intestine did not give rise to migratory neurons whatever the developmental stage. Regional differences in the development of migratory neurons may be correlated to the mechanism of the in vivo organization of the ganglionic chain. The present observations indicate that catecholamine-containing neurons in Remak's ganglion exhibit the same histochemical features as adrenergic sympathetic neurons and differentiate in short-term cultures.
Collapse
|
20
|
Guglielmone R, Cantino D. Autonomic innervation of the ocular choroid membrane in the chicken: a fluorescence-histochemical and electron-microscopic study. Cell Tissue Res 1982; 222:417-31. [PMID: 7083310 DOI: 10.1007/bf00213222] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The distribution pattern of adrenergic fibres innervating the ocular choroid membrane of the chicken was studied by means of fluorescence and electron microscopy. In addition, the origin of these fibres was investigated after superior cervical ganglionectomy. Adrenergic axons reach the choroid, partly forming the perivascular plexuses and partly running in the choroid nerves and the choroidal branches of the ciliary nerves. The axon terminals distribute to the smooth muscle cells of the arterial wall and to the extensive system of smooth muscle cells of the intervascular stroma. After unilateral ganglionectomy, fluorescent fibres almost completely disappeared, and degenerative changes could be observed in the terminal varicosities on both smooth muscle cell populations. These findings suggest that the adrenergic axons either originate from neurones within the ipsilateral superior cervical ganglion, or pass through this ganglion. The persistence of normal terminals in short- and long-term ganglionectomised animals shows that the vasal and intervascular muscle cells of the choroid membrane are provided with both an adrenergic and a cholinergic innervation.
Collapse
|
21
|
Cedrini L, Camino E, Alloatti G, Cantino D, Botto-Micca F. Contraction features in normal and hypodynamic lizard ventricle. J Physiol (Paris) 1981; 77:861-71. [PMID: 7341764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Isometric twitches and intra- and extracellular electrical activity were recorded at various driving rates from lizard ventricles, either in the normal inotropic state, or in a hypodynamic state induced by perfusing at a high flow rate for a long time. Electron micrographs were obtained from hearts fixed immediately after dissection and from preparations perfused in vitro for various periods. It was found that the peak of the steady-state strength-interval relationship shifts towards higher stimulation rates with the development of hypodynamia. Such a change is similar to that induced in normal preparations by perfusing with calcium-poor solutions. The normal strength-interval relationship can be restored in hypodynamic preparations by perfusion with a calcium-rich solution. Also, in the hypodynamic state, the action potential duration is increased and (+ dP/dt)max is decreased, while the shape of the staircases at various stimulation rates is modified. These changes occur in the presence of well-preserved ultrastructural features of the preparation. The results suggest that the twitch tension results from the contribution of two Ca ions fluxes: an early one from a cellular store, and a late one related to the action potential duration. The ultrastructural findings are consistent with the hypothesis that a store, from which a rapid release of calcium occurs, exists in the lizard ventricle. A hypodynamic state would be caused by a reduced calcium affinity of such store, and by a decreased Ca++ influx during the action potential plateau.
Collapse
|
22
|
Cantino D, Mosso R, Baccino FM. Changes induced by fasting and cycloheximide in the vacuolar apparatus of rat hepatocytes. A morphometric investigation. Boll Soc Ital Biol Sper 1979; 55:1884-9. [PMID: 553561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An increase in the number of autophagic vacuoles and in the size of the dense and residual bodies was observed in the hepatocytes of rats fasted for 24 hours; moreover, the number of dense bodies was reduced. These data suggest that the previously reported acceleration in cell protein degradation caused by fasting can be accounted for by enhanced autography. The treatment with cycloheximide, which was previously found to prevent this proteolytic response, also prevents the appearance of signs of enhanced autophagic activity.
Collapse
|
23
|
|
24
|
Cantino D, Mugnaini E. The structural basis for electrotonic coupling in the avian ciliary ganglion. A study with thin sectioning and freeze-fracturing. J Neurocytol 1975; 4:505-36. [PMID: 1176998 DOI: 10.1007/bf01351535] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Each "ciliary" neurone in the ciliary ganglion of adult birds receives its innervation from a single myelinated fibre of the oculomotor nerve by means of a dual mode of synaptic action, electrical and chemical. The preganglionic fibre branches repeatedly around the postganglionic axon but the extra-cellular compartment is large. The preterminal fibres, most of which are unmyelinated, end with large boutons on the axon hillock, a few on short dendrites and on the portion of the perikaryon of the ciliary neurone from which the axon emerges. This synaptic apparatus is enveloped by a glial sheath, mainly consisting of satellite cell bodies and loose myelin lamellae. The nonsynaptic portion of the ciliary perikaryon is covered by a sheath consisting mainly of compact myelin. The ciliary neurone has an initial axon segment like that of C.N.S. neurones. The area of each neurone apposed to boutons measures about 16,000 mum2. Approximately 9 percent is specialized for chemical transmission and 0.17 percent for electrical transmission. Each neurone has about 280,000 gap junctional particles. Assuming that each particle represents one channel, the electrical resistance provided by these junctions is estimated to be of the order of 100 k omega. The electrical coupling between the preganglionic fibre and the ciliary neurone may therefore be of resistive nature.
Collapse
|
25
|
Abstract
The chick ciliary ganglion receives a nonvascular symathetic innervation in addition to the well-known cholinergic one; fluorescent, varicose adrenergic fibers form pericelluar baskets. Adrenergic fibes were identified electron microscopically in ganglia fixed with potassium permanganate. The fibers degenerate after injection of 6-hydroxydopamine. No true synaptic relationships involving adrenergic varicosities and ganglion cells or cholinergic terminals were demonstrable. The distribution of the adrenergic fibers suggests a kind of "distance à synapse" with the choroidal cells or with the preganglionic fibers (or both). The adrenergic innervation might provide a modulation of the cholinergic transmission.
Collapse
|
26
|
|
27
|
|
28
|
Comoglio PM, Ottino G, Cantino D. Experimental study on development and behaviour of the multinucleated giant cells "in vitro". J Reticuloendothel Soc 1971; 9:397-408. [PMID: 5104806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
29
|
|
30
|
|
31
|
Cantino D, Comoglio P. [The distribution of motor plates in the mimic muscles of the dog (Canis familiaris L.)]. Boll Soc Ital Biol Sper 1966; 42:1201-3. [PMID: 5971143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
32
|
Pizzetti M, Cantino D, Siliquini PL, Pavetto GC, Dei Poli N. [Study of the evolution of experimental bone callous with the method of tetracycline fluorescence. IV]. Minerva Ortop 1966; 17:318-321. [PMID: 5963959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
33
|
Cantino D. [On the development of the intramural plexuses of the alimentary canal in the chick embryo]. Boll Soc Ital Biol Sper 1966; 42:411-3. [PMID: 5943046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|