An apparent somato-somatic synaptic structure in the pineal gland of the rat

Hopsu, V. K.; Arstila, Antti U.

doi:10.1016/0014-4827(65)90196-5

Cited by 58 publications

(11 citation statements)

References 2 publications

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“…According to Bunt [1971], the SR has a passive role in the synapse, in a conveyor belt fashion, along which synaptic vesicles are brought to wards the synaptic cleft for neurotransmitter release. Successively, Vollratlt [1973] was able to demonstrate that, in the pineal gland of the guinea pig, SR undergo a circadian, lightdependent rhythm: this author, in accordance with Hopsu and Arstila [1965], considers SR as a mean of connection between adjacent pinealo- cytes. Our results show that retinal SR are dynamic structures whose rapid turnover ex tends over the 24-hour cycle.…”

Section: Discussionmentioning

confidence: 96%

Ultrastructural data and chronobiological patterns of the synaptic ribbons in the outer plexiform layer in the retina of albino rats

Spadaro¹,

Simone²,

Puzzolo³

1978

Cells Tissues Organs

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Synaptic ribbons of the outer plexiform layer in the retina of albino rats are examined, with particular regard to their ultrastructure and to their chronobiological behaviour. As to the ultrastructure, aside from the typical lamellar and granular morphology, synaptic ribbons, whose central bar is roundish and granular, delaminate or furnished with enlarged extremities, are shown. As to the chronobiological pattern, synaptic ribbons undergo to circadian changes in their absolute number, being particularly numerous during the light phase, and few during darkness. It is also considered the morphology (ratio between granular and lamellar) and the size (long, intermediate and short) during the 24-hour cycle; in both cases, diphasic curves are observed. On the basis of these results, in the junction photoreceptors-bipolar cells, synaptic ribbons are polymorphic, dynamic structures, whose number and morphology strictly depend on environmental light conditions.

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Section: Discussionmentioning

confidence: 96%

Ultrastructural data and chronobiological patterns of the synaptic ribbons in the outer plexiform layer in the retina of albino rats

Spadaro¹,

Simone²,

Puzzolo³

1978

Cells Tissues Organs

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“…Examination of other cells with presynaptic ribbons, e.g., pinealocytes (Hopsu and Arstila, 1964) and mechanoreceptive hair cells of auditory, vestibular (Flock, 1964), and lateral-line sensory organs would be required to confirm this conclusion.…”

Section: Kif3a At Ribbon Synapsesmentioning

confidence: 99%

The Kinesin Motor KIF3A Is a Component of the Presynaptic Ribbon in Vertebrate Photoreceptors

1999

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Kinesin motors are presumed to transport various membrane compartments within neurons, but their specific in vivo functions, cargoes, and expression patterns in the brain are unclear. We have investigated the distribution of KIF3A, a member of the heteromeric family of kinesins, in the vertebrate retina. We find KIF3A at two distinct sites within photoreceptors: at the basal body of the connecting cilium axoneme and at the synaptic ribbon. Immunoelectron microscopy of the photoreceptor ribbon synapse shows KIF3A to be concentrated both at the ribbon matrix and on vesicles docked at the ribbon, a result that is consistent with the presence of both detergent-extractable and resistant KIF3A fractions at these synapses. KIF3A is also present in the inner plexiform layer, again at presynaptic ribbons. These findings suggest that within a single cell, the photoreceptor, one kinesin polypeptide, KIF3A, can serve two distinct functions, one specific for ribbon synapses.

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“…SR function has perhaps prematurely been considered synaptic in function. This hypothesis has been based on (1) the resemblance of SR vesicles to true synaptic vesicles, (2) the rare to occasional topographical relationship suggestive of axosomatic synaptic contact (pinealocyte SR: nerve terminal; Wolfe, 1965) or somatosomatic synaptic contact (SR in adjacent pinealocytes; Hopsu & Arstila, 1965), and (3) circadian changes in SR formation related to the gland's adrenergic innervation. Whether synaptic or not, the formation of SR is undoubtedly related to the innervation of pinealocytes by postganglionic, norepinephrine (NE)-containing axons originating in the superior cervi-cal ganglia.…”

Section: Introductionmentioning

confidence: 99%

Effect of denervation on ?synaptic? ribbon populations in the rat pineal gland

King

Dougherty

1982

J Neurocytol

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The formation of pineal 'synaptic' ribbons (SR) may be directly related to the adrenergic innervation of the gland. In order to clarify this relationship, SR populations at various times from 12 h to 14 days after pineal denervation were morphometrically analysed by electron microscopy. Pineal denervation was accomplished by bilateral superior cervical ganglionectomy. A decrease in nocturnal pineal SR numbers, indicating a reduction in SR formation, was demonstrated 12 to 24 h after pineal denervation. Seventy-two hours after ganglionectomy SR numbers were comparable with those in nocturnal intact and sham-operated controls. Thereafter, 7 and 14 days after ganglionectomy, SR numbers exceeded nocturnal intact and sham-operated controls. Administration of isoproterenol, a beta-adrenergic receptor agonist, 24 h after denervation significantly increased SR numbers over those in untreated rats denervated 24 h earlier. Thus SR formation remained responsive to adrenergic receptor stimulation in the absence of an intact adrenergic innervation. Further, the increase in SR numbers following subacute (7 to 14 days) denervation indicated that SR formation was not dependent on an intact innervation or the presence of endogenous (pineal) norepinephrine. On the basis of these results, we suggest that SR formation may be related structurally as well as functionally to adrenergic receptors on the rat pinealocyte.

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An apparent somato-somatic synaptic structure in the pineal gland of the rat

Cited by 58 publications

References 2 publications

Ultrastructural data and chronobiological patterns of the synaptic ribbons in the outer plexiform layer in the retina of albino rats

Ultrastructural data and chronobiological patterns of the synaptic ribbons in the outer plexiform layer in the retina of albino rats

The Kinesin Motor KIF3A Is a Component of the Presynaptic Ribbon in Vertebrate Photoreceptors

Effect of denervation on ?synaptic? ribbon populations in the rat pineal gland

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