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J C Desclin

Publications and source records attributed to J C Desclin.

11 recordsLinked to original sources
PubMed1983

Pituitary-dependent renin-like immunoreactivity in the rat testis.

By means of a specific anti-rat renin antiserum, immunohistochemical staining was observed restricted to Leydig cells of rat testis. Specificity of the staining was ascertained by the absence of reaction with nonimmune serum or with the antiserum preincubated with rat renin. Specific staining of Leydig cells was absent in newborn rats; it developed with the onset of puberty. Staining was suppressed or abolished by hypophysectomy and estrogen treatment and was reduced by gonadotropin stimulation. Vasectomy destroyed the seminiferous epithelium but did not impair renin-like immunoreactivity of the interstitial tissue. It is concluded that Leydig cells contain a pituitary-dependent renin-like substance.

Age Factors↗
PubMed1980

The olivocerebellar system. I. Delayed and slow inhibitory effects: an overlooked salient feature of cerebellar climbing fibers.

(1) Chemical destruction of the inferior olive (ION), or midline section interrupting the climbing fibers (CFs) rapidly resulted in marked modifications of Purkinje cell (P. cell) simple spike (SS) firing rate and pattern. (2) After CF deafferentation, P. cells at first about doubled their SS frequency which further increased for the next 10 min. (3) Besides the increase in the firing rate, the spike train became much more regular, which in part seemed to be linked to mass oscillations of the neuronal circuitry, as revealed by strong oscillations of background noise. (4) After ION destruction CF activity could be supplied for by juxtafastigial (JF) stimulation which reduced SS frequency again while the firing became much less regular. These effects were shown to be due to the all-or-nothing activity of the CF and not to the simultaneous stimulation of mossy fibers (MFs) or P. cell axons. Neither were they ascribable to CF collaterals. The differences between this new powerful inhibitory action of the CF system on the P. cell and the well documented pause mechanism is discussed. (5) A quantitative relationship has been established between complex spikes (CSs) and SS firing rates. A steady 2/sec CS frequency was shown to effectively silence the P. cell. (6) When CF stimulation was discontinued, an "off" effect was described. It consisted of an initial rise in SS frequency developing in 9 sec, and a delayed further increase unfolding in about 10 min. (7) When CF stimulation began, an "on" effect was observed, which evolved with an exponential-like kinetic of very variable time-constant seemingly depending on past history.

Afferent Pathways↗
PubMed1980

The olivocerebellar system. II. Some ultrastructural correlates of inferior olive destruction in the rat.

Short- and long-term ultrastructural changes induced in rat inferior olivary nucleus (ION) and cerebellum by a single injection of 3-acetylpyridine (3-AP) were investigated. Evidence of perikaryal and dendritic alterations was already present in numerous ION neurons at 3 h after injection. All ION neurons were affected at 6 h. Complete destruction of the entire ION was achieved within 8-10 h. Time-course and cytological features of this degeneration were described. Total absence of axonal termination degeneration in the ION or at its periphery ruled out the existence of recurrent olivary axons in these locations. Climbing fiber (CF) terminal degeneration in the cerebellar cortex apparently was restricted to the molecular layer, which cast serious doubts on the existence of glomerular collaterals of CFs. Evidence of axonal terminal degeneration was observed within all cerebellar nuclei at 24 and 26 h after 3-AP treatment, but degenerating profiles were unexpectedly infrequent. Consequential to CF deafferentation, Purkinje cells (P.cells) underwent both precocious and delayed ultrastructural changes. Delayed and long-range changes involved mainly dendrites and perikarya. Axon terminals underwent precocious but prolonged alterations which were interpreted as evidence supporting enhanced synaptic activity of P. cells deprived of CFs.

Afferent Pathways↗
PubMed1976

Early terminal degeneration of cerebellar climbing fibers after destruction of the inferior olive in the rat. Synaptic relationships in the molecular layer.

The cerebellar molecular layer in adult rats has been studied with the electron microscope at several early and consecutive survival times following 3-acetylpyridine intoxication. Climbing fiber (CF) terminals underwent a fast process of electron-dense degeneration which became apparent from 16 hours onwards. A small proportion of degenerating terminals were depleted of vesicles and filled with a dark flocculent and granular homogeneous matrix. Microtubular changes in degenerating CF tendrils were observed. CF terminals were found in relation with every Purkinje cell in normal animals and completely disappeared within 72 hours after the treatment. CF synapses were found on Purkinje dendritic and somatic thorns, sometimes also on the dendritic shafts or even on the Purkinje soma. Convincing evidencd of synaptic contacts of CF varicosities on either basket or stellate cells could not be obtained. CF synapses with Golgi II cell dendrites in the molecular layer were described. Decrease in the number of post-synaptic dendritic thorns normally assigned for CF synapses was observed consequential to CF anterograde degeneration. The observations are consistent with previous conclusions drawn from light microscopic studies that the clearing up of CF debris in the molecular layer is completed within the short time of three days, and that the inferior olive seems to be the only source of CFs.

Animals↗
PubMed1975

An additional silver impregnation method for demonstration of degenerating nerve cells and processes in the central nervous system.

A new silver impregnation technique for frozen and paraffin sections of formalin-fixed nervous tissue has been devised by modifying the Fink-Heimer14 and De Olmos-Ingram6 methods. The modified versions have been combined into a single staining procedure. Cobalt or lead nitrate are substituted for uranyl nitrate. Silver nitrate in the impregnating solution is replaced by silver lactate or protargol. This procedure results in a preferential impregnation of degenerating perikarya, dendrites, axons and synaptic endings. It affords a more complete impregnation of 'preterminal' axonal arborizations than previous methods. The method is effective for the demonstration of degenerating terminals in the rat cerebellar cortex. Emphasis has been laid on the usefulness of the method for the study of drug-induced CNS lesions.

Animals↗