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J R Sladek

Publications and source records attributed to J R Sladek.

At least 127 records · Page 7Linked to original sources
PubMed1976

Monosodium glutamate induced lesions of the arcurate nucleus. II. Fluorescence histochemistry of catecholamines.

The effect of the monosodium glutamate (MSG) induced lesion of the arcuate nucleus on catecholamines in the arcuate nucleus and median eminence of the mouse hypothalamus was determined using the Falck-Hillarp histofluorescence technique. The number of fluorescent perikarya in the arcuate nucleus of treated animals was decreased approximately 60%; the fluorescence intensity of surviving neurons was notably reduced. These changes were accompanied by a reduction in the intensity of fluorescence in the median eminence. Pretreatment of control and MSG-lesioned animals with a monoamine oxidase inhibitor (pargyline) greatly increased fluroescence in the median eminence and arcuate nucleus of both groups. However, the number of fluorescing perikarya of the arcuate nucleus of the normal pargyline treated group far exceeded that of the pargyline MSG animals. It is concluded that neonatally administered MSG caused destruction of a large number of dopaminergic arcuate perikarya.

Animals↗
PubMed1975

Catecholamine distribution in feline hypothalamus.

Catecholamine distribution was examined in cat hypothalamus using the histochemical fluorescence technique of Falck and Hillarp. The heaviest accumulations of catecholamine-containing varicosities were seen within the: anterior periventricular nucleus; dorsal hypothalamic area; bed nucleus of the inferior thalamic peduncle; doral component of the paraventricular nucleus; dorsomedial nucleus; infundibular nucleus; bed nucleus of the stria terminalis-medial division; and supraoptic nucelus. Catecholaminergic perikarya were observed within periventricular, dorsal, and caudal hypothalamic areas as well as within the supramamillary nucleus and caudal diencephalon. Catecholamine distribution in cat hypothalamus possesses both similarities and dissimilarities in relation to distributions reported in other mammals.

Animals↗
PubMed1975

The distribution of catecholamines within the inferior olivary complex of the cat and rhesus monkey.

Catecholamine histofluorescence was examined in the interior olivary complex of the cat and rhesus monkey. Species-specific patterns of catecholamine-containing varicosities were observed. In the rat, the highest concentration of catecholamine varicosities was seen within the dorsal lamella of the principal nucleus. In contrast, this same portion of the inferior olivary complex appeared void of catecholamine varicosities in the cat and rhesus monkey. In the cat, the highest concentration of varicosities occurred within the medial one-half of the dorsal accessory nucleus while few, if any, varicosities were seen in this portion of the complex in the rat and monkey. The lateral lamella of the principal nucleus contained the highest concentration seen in the rhesus monkey, a finding which contrasts to the minimal number of varicosities seen in this area in the rat and cat. Catecholamine-containing cell bodies, reported to exist in the rat, were not observed in cat and monkey. These data extend the previous observation of species-specific distribution in rodents to include members of the more phylogenetically advanced orders; Carnivora and Primata. Catecholamines were found primarily within those portions of the olivary complex reported to be involved in harmaline-induced tremor activity in the cat.

Age Factors↗
PubMed1975

Monoamine distribution in primate brain. I Catecholamine-containing perikarya in the brain stem of Macaca speciosa.

The distribution of catecholamine-containing cell bodies was examined in the brain stem of Macaca speciosa using the Falck-Hillarp histofluorescence technique. Extensive accumulations of such cells were seen in the ventral tegmental area, locus coeruleus, mesencephalic reticular formation and ventrolateral reticular formation of pons and medulla. This distribution was compared to that previously reported in rat, cat, squirrel monkey and human brain. Apparent species dissimilarities and similarities are reported.

Animals↗
PubMed1971

Differences in the distribution of catecholamine varicosities in cat and rat reticular formation.

The distribution of catecholamine varicosities within the brainstem reticular formation of the immature cat was determined by means of the formaldehyde-induced fluorescence technique. A continuous pattern of intense, green, medium-sized varicosities exists at nearly all brainstem levels. At most of these levels the varicosities appear within the boundaries of reticular formation nuclei. However, in rostral mesencephalon, some of the varicosities of the pattern lie in proximity to perikarya of the red nucleus. In addition, numerous varicosities in caudal medulla appear to extend from the pattern into nonreticular formation nuclei. A comparable pattern of reticular formation fluorescence is absent in the rat and this finding is believed to represent a true interspecies difference.

Anatomy, Comparative↗
PubMedDate not supplied

Apolipoprotein E-immunoreactivity in aged rhesus monkey cortex: colocalization with amyloid plaques.

In the present study, we examined the relationship between ApoE and amyloid containing profiles within the cerebral cortex of young, middle aged, and aged Rhesus monkeys. Polymerase chain reaction analysis revealed a pattern consistent with the ApoE e4 phenotype in the rhesus monkey similar to that reported in humans. We found numerous ApoE immunoreactive plaques within the temporal neocortex and amygdala, whereas the hippocampus contained only a few such plaques. Although virtually all ApoE-immunoreactive plaques coexpressed beta-amyloid, most plaques were beta A4 positive/ApoE immunonegative within the aged monkey cortex. Moreover, we observed a close correspondence between ApoE and thioflavin-positive (i.e., amyloid) plaques suggesting that ApoE may play a critical role in the conversion of beta A4 to its beta-pleated form. Because ApoE, beta A4 and amyloid are expressed in plaques within the aged Rhesus macaque cortex, this species may provide an in vivo model for investigations aimed at clarifying the interactions between these proteins in normal and pathologic aging.

Aging↗
PubMedDate not supplied

Simultaneous monoamine histofluorescence and neuropeptide immunocytochemistry: V. A methodology for examining correlative monoamine-neuropeptide neuroanatomy.

A technique for the simultaneous visualization of monoamines and neuropeptides is described. This technique provides for the correlative examination of monoamine and neuropeptide interrelationships either simultaneously using two adjacent sections of freeze-dried tissue or sequentially using a single freeze-dried tissue section for both histofluorescence and immunocytochemistry. Both techniques provide for the investigation of precise anatomical interrelationships and used together provide confirmation and complementary information concerning neuropeptide-monoamine interactions. Histological comparisons between freeze-dried and Bouin's fixed tissue revealed three differences: First, the cytoplasm of neurons in freeze-dried tissue retained a reticulated appearance; secondly, neurons in freeze-dried tissue demonstrated a greater affinity for chemical stains; and thirdly, tissue fixed in Bouin's solution appeared shrunken when compared to tissue which had been freeze-dried. Application of immunocytochemistry to freeze-dried tissue proved successful with all antisera tested and the quality of the immunostaining was similar in both freeze-dried and Bouin's fixed tissue. These observations suggest that freeze-drying fixation provides a suitable tissue preparation for immunocytochemistry and a technical means for coupling immunocytochemical staining of neuropeptides and fluorescence histochemical methods for monoamines in a single tissue block.

Animals↗
PubMedDate not supplied

Simultaneous monoamine histofluorescence and neuropeptide immunocytochemistry: VI. Catecholamine innervation of vasopressin and oxytocin neurons in the rhesus monkey hypothalamus.

The co-localization patterns of catecholamine varicosities and peptide-specific neuronal perikarya were assessed within the supraoptic and paraventricular nuclei in the rhesus monkey, Macaca mulatta. Formaldehyde-induced histofluorescence was coupled with the unlabelled antibody technique for the demonstration of neuropeptides. Hormone-specific neurophysin staining served to identify vasopressin and oxytocin-containing neurons in these hypothalamic nuclei. Catecholamine varicosities were seen in juxtaposition to vasopressin- and oxytocin-containing perikarya and proximal dendrites. The densest catecholamine innervation patterns were seen in the ventrolateral portion of the supraoptic nucleus; the dorsomedial portion of this nucleus received a considerably less dense innervation pattern. Oxytocin neurons were clustered in this relatively catecholamine poor region, whereas the vasopressin-containing neurons were more abundantly found in the catecholamine rich region. The paraventricular nucleus presented a considerably more complex pattern, perhaps reflecting the more diverse organization of this nucleus. Nevertheless, some separation of the oxytocin neurons, in a region less densely innervated by catecholamine varicosities, was noted. These observations confirm our earlier reports, in rat hypothalamus, that the norepinephrine innervation of the hypothalamic magnocellular neurons as seen with catecholamine histofluorescence favors the vasopressin-containing neurons over those located within the same nuclei which synthesize another neurohyphysial principal, oxytocin.

Animals↗
PubMedDate not supplied

Sham surgery does not ameliorate MPTP-induced behavioral deficits in monkeys.

Parkinsonism has been reported to improve following transplantation of fetal mesencephalic tissue into the striatum of MPTP-exposed monkeys and humans and in patients with idiopathic Parkinson's disease. While there is good evidence for the survival of grafted tyrosine hydroxylase (TH)-positive cells in animal studies, it is not known whether they produce neuronal effects that account for behavioral improvement after transplantation or whether spontaneous or graft-induced changes in the host striatum are at least partly responsible. Are neuronal synaptic connections and dopamine release necessary, or would "toenails and talcum powder" do the job equally well? We have addressed these questions by studying several types of implantation surgeries, including sham surgery, the implantation of cerebellar tissue, and the implantation of mesencephalic TH-positive fetal tissue of various gestational ages into the striatum. Adult male African green monkeys received systemic MPTP administration (cumulative doses of 2.0-2.5 mg/kg) prior to these stereotaxic surgical manipulations. Subjects were matched for quantitative behavioral deficits prior to surgery. Subjects were examined and assessments made by "blinded" observers who scored individual spontaneous and elicited behaviors. Observers were trained and tested repeatedly for inter-rater reliability. A "parkinsonian summary score" derived and determined using a principal component factor analysis of a large sample of data from MPTP-treated and normal monkeys of the same species was used to assess behavior. Postmortem brain tissue was prepared for biochemical analysis of dopamine concentrations and TH immunohistochemical studies. The most dramatic improvement was seen in monkeys with "early" (< 4 cm fetal crown rump length) surviving substantia nigra grafts in the caudate nucleus. Some behavioral improvements were seen in MPTP-treated sham-operated monkeys, cerebellar-grafted monkeys, and "later" (> 14 cm fetal crown rump length) substantia nigra-grafted monkeys. These changes in monkeys which did not have surviving dopamine-producing grafts probably represent the recovery capacity of MPTP-treated host brain during this time interval since un-operated subjects showed similar changes. More variable effects were seen with substantia nigra grafts in the putamen. The most consistent correlate of behavioral improvement in all experimental groups was elevation in dopamine concentrations near the grafts compared with a distant striatal location which is believed to represent the depletion without the effects of the grafts. While these data do not establish the precise mechanism of action, they point to a hierarchy of factors which provide increasingly larger restorative effects, including sprouting of host neurons and increased dopamine production by grafted fetal dopamine neurons. Sham surgery appears to be significantly less effective than early fetal mesencephalic tissue which survives and releases dopamine.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗