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R Y Moore

Publications and source records attributed to R Y Moore.

At least 109 records · Page 6Linked to original sources
PubMed1987

Differentiation of the suprachiasmatic nucleus in fetal rat anterior hypothalamic transplants in oculo.

The capacity of the rat anterior hypothalamus, and particularly the suprachiasmatic nucleus (SCN), to develop and differentiate when removed from its normal environment was examined in this study using light and electron microscopy. The hypothalamus from fetuses ranging in age from embryonic day 12 (E 12) to E 16 was transplanted to the anterior chamber of the eye of adult rats. In initial experiments, we found that transplants from E 15 fetuses and older routinely differentiated into fields of neurons with extensive neuropil with an appearance similar to the anterior hypothalamic area. Groups of small, compactly organized neurons were observed only occasionally in this tissue. Ultrastructural analysis of these transplants typically revealed well-differentiated neuronal perikarya and neuropil with a complex synaptic organization similar in appearance to the normal rat anterior hypothalamic area. Occasionally both mature and immature tissue coexisted in some of the transplants. Tissue from young embryos (E 12-14) frequently showed development of a compact, small neuron nucleus with the cytoarchitectonic appearance of the SCN. At least 45 days were required after transplantation for the successful differentiation to occur in this situation. The SCN in these transplants displayed vasoactive intestinal polypeptide-immunoreactive cells and fibers surrounded by vasopressin-immunoreactive cells and fibers, similar to the pattern observed in the normal adult SCN. Our results indicate that the anterior hypothalamus will differentiate normally in oculo and that the phenotypic specification of the SCN occurs prior to the birthdate of its component neurons.

Animals↗
PubMed1987

Development of neuronal activity in the rat suprachiasmatic nucleus.

The development of function was studied in the rat suprachiasmatic nucleus (SCN) by analyzing the rate and pattern of neuronal discharge in vitro from embryonic day 22 (E22) to postnatal day 14 (P14), and comparing these with adult SCN. The firing rate of SCN neurons on E22 is low but there is a clear circadian rhythm with subjective day values (1.6 +/- 0.2 impulses/s) significantly higher than those for subjective night (0.9 +/- 0.2 impulses/s). At E22 most neurons show an irregular firing pattern. The firing rate of SCN neurons gradually increases from E22 to P14 with emergence of patterns of firing of individual neurons that approximate those of adult SCN. In calcium-free medium the firing rate of SCN neurons at P1 is reduced and the circadian rhythm in firing rate is abolished. These results demonstrate that SCN neurons exhibit a circadian rhythm in firing rate early in development, largely prior to the formation of synaptic contacts within the SCN, and indicate that expression of the rhythm requires the presence of calcium ions.

Action Potentials↗
PubMed1986

Neuropeptide Y localization in the rat amygdaloid complex.

Neuropeptide Y (NPY)-, avian pancreatic polypeptide (APP)-, and molluscan cardioexcitatory peptide (FMRF)-like immunoreactivity in the amygdaloid complex of the rat was investigated immunohistochemically. The distribution of each of these peptides within the amygdala is identical and cross-blocking studies indicate that all three antisera recognize the NPY antigen. Morphologically distinct populations of NPY immunoreactive neurons are differentially distributed in the medial amygdaloid nucleus and at the base of the stria terminalis. Dense plexuses of immunoreactive axons are present in the medial third of the central nucleus and in the dorsal half of the medial nucleus, with light to moderate fiber plexuses present in the lateral and basolateral nuclei and scattered axons present throughout the remainder of the amygdala. The distribution and appearance of NPY immunoreactive plexuses in the amygdala is similar to that described previously for noradrenergic axons arising from brainstem cell groups (Fallon, Koziell, and Moore: J. Comp. Neurol. 180:509-532, '78). However, injections of the noradrenergic neurotoxin 6-hydroxydopamine into the amygdala result in a complete loss of dopamine-beta-hydroxylase (DBH) immunoreactivity in the amygdala and surrounding cortex but leave much of the NPY immunoreactive plexus intact. Similarly, lesions of the locus coeruleus deplete DBH immunoreactivity, leaving NPY-like immunoreactivity in the amygdala unaffected. These results indicate that much of the NPY immunoreactive plexus observed in the amygdala does not arise from brainstem sources in which NPY and noradrenaline are colocalized. Lesions of the stria terminalis or medial nucleus have no observable effect on the density or distribution of NPY immunoreactive terminal fields in the basal forebrain and hypothalamus, suggesting that immunoreactive neurons in the amygdaloid complex do not contribute significantly to this innervation.

Amygdala↗
PubMed1986

Synaptic reorganization in the motor trigeminal nucleus of the rat following neonatal 6-hydroxydopamine treatment.

The synaptic organization of the motor trigeminal nucleus in adult rats treated neonatally with 6-hydroxydopamine (6-OHDA) was investigated quantitatively and compared with control nuclei. No statistically significant change was detected in the distribution of axon terminals in the neuropil, and the total number of axosomatic contacts per unit length of membrane was identical in the control and 6-OHDA-treated groups. However, 6-OHDA treatment causes a significant redistribution of the four morphologically distinct bouton populations forming axosomatic contacts with trigeminal motoneurons. Terminals containing lucent axoplasm and spherical synaptic vesicles have been identified as norepinephrine neuron terminals (Card et al.: J. Comp. Neurol. 250:469-484, '86). These and terminals with lucent axoplasm and pleomorphic vesicles are increased in number whereas terminals with dense axoplasm and either spherical or pleomorphic synaptic vesicles are decreased in number in the 6-OHDA-treated brains compared to controls. These results confirm that the norepinephrine hyperinnervation observed in histofluorescence preparations following neonatal 6-OHDA treatment reflects an increase in absolute numbers of norepinephrine terminals. The finding that the total number of axosomatic contacts per unit length of membrane remains constant while the proportions of individual afferent classes vary may indicate that the trigeminal motoneuron plays a major role in determining the overall density but not necessarily the individual specificity of its axosomatic innervation. The motor trigeminal nucleus is a useful model system in which to investigate both the response of norepinephrine fibers to neonatal 6-OHDA treatment and the respective roles of a target neuron and its afferents in the regulation of appropriate quantitative innervation patterns in the central nervous system.

Animals↗
PubMed1986

The motor trigeminal nucleus of the rat: analysis of neuronal structure and the synaptic organization of noradrenergic afferents.

The organization of the rat motor trigeminal nucleus (MTN) and the morphology of noradrenergic afferents terminating in this cranial motor nucleus were analyzed with light and transmission electron microscopy. Two morphologically distinct types of neurons are present in the MTN. Large multipolar neurons are the most prevalent cell type and are distributed uniformly throughout the nucleus. The morphology of these cells is identical to that of motor neurons described previously in both the brainstem and spinal cord. The neurons are characterized ultrastructurally by a light, organelle-rich cytoplasmic matrix containing numerous cisternal arrays of rough endoplasmic reticulum (RER) and a centrally placed spherical nucleus containing a single prominent nucleolus. Approximately 80% of the surface of these cells is contacted by axon terminals. The second major class of neuron consists of small spherical and fusiform cells that are located predominantly at the peripheral borders of the MTN. These cells are significantly smaller than motor neurons and exhibit only scattered axosomatic contacts. This small cell population appears to be composed of two distinct subclasses of neurons that probably represent interneurons and gamma motor neurons. The MTN neuropil contains four morphologically distinct classes of axon terminals that are characterized by either spherical or pleomorphic vesicles within cytoplasm that is lucent or dense. Quantitative morphometric analysis demonstrated differential distribution of each of the four terminal types upon motor neuron somata and dendrites. Intracerebral injection of 5-hydroxydopamine into the brainstem tegmentum immediately adjacent to the MTN labeled axon terminals containing spherical vesicles and a lucent axoplasmic matrix. Intracerebral injection of the neurotoxin 6-hydroxydopamine resulted in degeneration of the same terminal population and thus confirmed that noradrenaline-containing axons innervating the MTN exhibit a distinctive terminal morphology. The number of synaptic complexes exhibited by noradrenergic terminals did not differ significantly from other terminal populations in the MTN.

Animals↗
PubMed1985

Suprachiasmatic nucleus ablation abolishes circadian rhythms in rat brain neurotransmitter receptors.

The effect of suprachiasmatic nucleus (SCN) ablation on rhythms in brain neurotransmitter receptors was studied. In control animals, the rhythms in the number of alpha-adrenergic and benzodiazepine receptors were circadian, whereas the rhythms in beta-adrenergic and acetylcholine receptors were ultradian. SCN ablation resulted in loss of circadian, but not ultradian, rhythms, without change in the 24-h mean numbers. SCN ablation appears to cause a selective loss of circadian function in the regulation of brain receptors.

Animals↗
PubMed1984

Afferent connections of the ventral lateral geniculate nucleus in the rat: an HRP study.

The afferent connections of the ventral lateral geniculate nucleus (VLGN) of the albino rat were studied using the HRP-retrograde transport method. Neurons projecting to the VLGN were found in 4 visual systems areas: layer V of the ipsilateral visual cortex (areas 17 and 18), the stratum griseum superficiale of the ipsilateral superior colliculus, the ipsilateral olivary, anterior and posterior pretectal nuclei and in the contralateral medial divisions of the VLGN. Labeled neurons were also found bilaterally in the nucleus raphe dorsalis and nucleus locus coeruleus.

Afferent Pathways↗
PubMed1984

Distribution of enkephalin, substance P, tyrosine hydroxylase, and 5-hydroxytryptamine immunoreactivity in the septal region of the rat.

Immunocytochemical methods were used to define the distribution of enkephalin (ENK), substance P (SP), tyrosine hydroxylase (TH), and serotonin (5-hydroxytryptamine: 5HT) in the rat septum. A dense plexus of axons containing enkephalin-like immunoreactivity is found in the intermediate lateral septal nucleus. This is surrounded laterally by SP-containing cell bodies and axons and medially by ENK-containing cell bodies. Both SP- and ENK-immunoreactive axons form pericellular and peridendritic terminal arbors around lateral septal neurons. TH-positive axons are distributed throughout the septum and form dense pericellular terminal baskets around scattered neurons in the medial half of the intermediate lateral septal nucleus and in the extreme lateral septum. Very few SP and TH immunoreactive axons are present in the ENK immunoreactive plexus zone. 5HT-immunoreactive axons are most dense at the lateral edge of the ventral and intermediate lateral septal nuclei but form pericellular terminal arbors only in the dorsal lateral septal nucleus, in the septofimbrial nucleus, and in the dorsal cap of the medial septal nucleus. These results indicate that the dorsal and intermediate lateral septal nuclei include three histochemically distinct laminated subfields: (1) an ENK immunoreactive axonal plexus within the lateral aspect of the intermediate lateral septal nucleus, (2) a more medial region of scattered ENK immunoreactive perikarya and similarly scattered TH immunoreactive pericellular baskets, and (3) a dorsolateral zone occupied by SP neurons and 5HT-containing pericellular baskets. Thus, the data suggest that SP- and ENK-containing neuronal populations in the lateral septum receive different monoaminergic inputs. Further, the somewhat exclusive laminated pericellular termination of peptide- and catecholamine-containing axons in the lateral septum predicts very different functional and pharmacological properties among zones.

Animals↗
PubMed1984

Identical immunoreactivity of afferents to the rat suprachiasmatic nucleus with antisera against avian pancreatic polypeptide, molluscan cardioexcitatory peptide and neuropeptide Y.

Avian pancreatic polypeptide (APP)-like, molluscan cardioexcitatory peptide (FMRF)-like and neuropeptide Y (NPY)-like immunoreactivities were studied in a secondary visual pathway in rat brain. The cell bodies of this pathway are located in the lateral geniculate nucleus and its terminal plexus is found in the suprachiasmatic hypothalamic nucleus (SCN). The neurons and terminal plexus demonstrated by antiserum to each peptide are identical, and immunoreactivity is blocked by preabsorption of each antiserum with a low concentration of the antigen against which it was raised. Immunoreactivity is also blocked by preabsorption of each antiserum with either NPY or APP. In contrast, APP- and NPY-like immunoreactivities are blocked only partially when these antisera are preabsorbed with concentrations of FMRF as high as 100 microM. Since NPY is the only one of these peptides that has been isolated from mammalian brain, we conclude that NPY is the endogenous CNS peptide produced by neurons of the lateral geniculate-SCN projection.

Afferent Pathways↗
PubMed1984

The suprachiasmatic nucleus of the golden hamster: immunohistochemical analysis of cell and fiber distribution.

The distribution of vasopressin-, vasoactive intestinal polypeptide-, somatostatin-, avian pancreatic polypeptide-, 5-hydroxytryptamine- and glutamic acid decarboxylase-like immunoreactivity was analyzed in the suprachiasmatic nuclei of male and female golden hamsters. Vasopressin. Vasopressin-like immunoreactivity is localized within neurons, dendrites and axons throughout the rostrocaudal extent of the suprachiasmatic nuclei. Immunoreactive perikarya are restricted to the dorsomedial aspect of each nucleus and occur in highest numbers within the intermediate two-thirds of the rostrocaudal axis. Axons containing vasopressin-like immunoreactivity form a dense plexus in the dorsomedial suprachiasmatic nuclei and in a vertical column at the lateral aspect of each nucleus. Somatostatin. Somatostatin-like immunoreactivity is also contained in neurons in the dorsomedial aspect of the suprachiasmatic nuclei and in thin varicose axons distributed throughout the suprachiasmatic nuclei in a pattern similar to that of vasopressin-immunoreactive axons. Vasoactive intestinal polypeptide. Vasoactive intestinal polypeptide-immunoreactive neurons are concentrated in the ventrolateral portion of each nucleus and occur almost exclusively within the intermediate two-thirds of the rostrocaudal axis. An extremely dense plexus of varicose axons exhibiting vasoactive intestinal polypeptide-like immunoreactivity extends throughout the suprachiasmatic nuclei and passes out of the dorsal aspect of each nucleus into the periventricular and anterior hypothalamic areas. Avian pancreatic polypeptide. Avian pancreatic polypeptide-like immunoreactivity is restricted to axons which arborize within the ventrolateral aspect of each nucleus. These fibers extend throughout the rostrocaudal extent of each nucleus and partially overlap the terminal field of retinal afferents. Glutamic acid decarboxylase. A very dense plexus of axonal varicosities exhibiting glutamic acid decarboxylase-like immunoreactivity fills both the dorsomedial and ventrolateral portions of the suprachiasmatic nuclei throughout the rostrocaudal extent of each nucleus. Lightly stained immunoreactive perikarya also occur throughout the suprachiasmatic nuclei. 5-Hydroxytryptamine. 5-Hydroxytryptamine-like immunoreactivity is restricted to axons which form a plexus in the ventromedial portion of each nucleus that is most dense in the intermediate two-thirds of the rostrocaudal axis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Interpeduncular nucleus organization in the rat: cytoarchitecture and histochemical analysis.

The organization of the interpeduncular nucleus (IPN) in the adult rat was analyzed using cytoarchitectonic, histochemical and immunohistochemical methods. Four paired and four unpaired subnuclei can be distinguished in the IPN on the basis of neuronal size, morphology, staining characteristics and packing density. The rostral portion of the IPN contains a rostral dorsal, a rostral ventral and paired rostral lateral and dorsal lateral nuclei. The dorsal lateral nuclei continue into the caudal IPN, which also contains a caudal dorsal, a caudal ventral and paired caudal lateral nuclei. The distribution of extrinsic afferents and of chemically identified intrinsic neuronal and fiber populations within subdivisions of the IPN was examined using immunohistochemistry, acetylcholinesterase histochemistry, catecholamine histofluorescence and the autoradiographic tracing method. Six immunohistochemically distinct neuronal groups are identified in the IPN. Perikarya and axons showing substance P-, leu-enkephalin-, somatostatin-, avian pancreatic polypeptide-, serotonin- and glutamic acid decarboxylase-like immunoreactivity are localized to specific IPN subnuclei. Acetylcholinesterase-positive staining, extrinsic norepinephrine-containing fibers and afferents from the dorsal tegmental nuclei are also distributed specifically to IPN subnuclei. These findings demonstrate a cytoarchitectonic and cytochemical complexity in the rat IPN that implies an important functional role for this poorly understood nuclear complex.

Acetylcholinesterase↗
PubMed1983

Immunohistochemical localization of avian pancreatic polypeptide-like immunoreactivity in the rat hypothalamus.

The distribution of avian pancreatic polypeptide-like (APP) immunoreactivity within the rat hypothalamus was investigated with the indirect immunoperoxidase method. APP immunoreactive perikarya are found in largest numbers in the retrochiasmatic area, the arcuate nucleus, and the supracommissural portion of the interstitial nucleus of the stria terminalis. Small clusters of immunoreactive neurons are also consistently observed in the ventral aspect of the medial preoptic area and lateral hypothalamic area, immediately dorsolateral to the optic chiasm and tracts. These neurons are apparent in all animals but are more intensely strained and occur in larger numbers following colchicine pretreatment. Other immunoreactive neurons are visible only in colchine-treated rats and are scattered throughout the anterior and lateral hypothalamic areas and the supramammillary nucleus. Immunoreactive axons and terminal fields present an extensive and highly characteristic distribution throughout the hypothalamus, which in many instances exhibits differential distribution within specific subfields of hypothalamic nuclei and areas. The heaviest concentrations of APP immunoreactive axons are present in the periventricular nucleus throughout the rostrocaudal extent of the hypothalamus, the ventrolateral portion of the suprachiasmatic nucleus, the retrochiasmatic area, the parvocellular paraventricular nucleus, the ventral supraoptic nucleus, the perifornical nucleus, the ventral dorsomedial nucleus, and the arcuate nucleus. Moderate plexuses of immunoreactive fibers are also present in the medial preoptic area, the anterior and lateral hypothalamic areas, the nucleus circularis, the median eminence, and the ventral premammillary area. Other areas, such as the ventromedial nucleus, contain virtually no immunoreactive axons but are encapsulated by a dense plexus of immunoreactive terminals. The distribution of a major component of APP immunoreactive fibers exhibits a marked similarity to that of previously described norepinephrine-containing hypothalamic afferents. Other groups of APP immunoreactive perikarya and fibers appear to represent components of intrinsic diencephalic systems.

Animals↗
PubMed1983

Neurotransmitter histochemistry: comparison of fluorescence and immunohistochemical methods.

The above procedures clearly demonstrate the effectiveness of the fluorescence histochemical and immunohistochemical methods in analysis of central CA neuron systems. Each method is well characterized and possesses sufficient versatility to permit a variety of experimental applications. The fluorescence histochemical technique is extremely reliable, produces good cell and fiber morphology, and has served as the fundamental procedure used to define the organization and distribution of CA-containing neurons throughout both the central and peripheral nervous system. However, the basic method makes no distinction between individual catecholamine neuron systems unless combined with mechanical or chemically induced lesions. The immunohistochemical technique relies upon the availability of antisera generated against the catecholamine-synthesizing enzymes tyrosine hydroxylase (TH), dopamine beta-hydroxylase(DBH), and phenylethanolamine N-methyltransferase (PNMT). Each of these enzymes catalyzes different steps in catecholamine metabolism and therefore can be used in conjunction with one another to selectively delineate the organization and distribution of neuronal cells and processes containing dopamine (TH), noradrenaline (TH and DBH), and adrenaline (PNMT). In addition, the immunohistochemical method may be coupled with the fluorescence histochemical technique, dual-labeling immunohistochemical methods, and retrograde tract tracing methods to provide further information on the interrelations of individual CA systems with one another and other chemically distinct systems of neurons. The usefulness of the immunohistochemical method in elucidating the organization of separate systems of CA-containing neurons is illustrated in a recent study by Swanson and collaborators. Utilizing antisera raised against the previously mentioned CA synthesizing enzymes, they analyzed the organization of CA systems within the paraventricular and supraoptic nuclei of the hypothalamus. By combining this analysis with immunohistochemical staining with antisera generated against vasopressin and oxytocin, they were able to demonstrate differential distribution of adrenergic and noradrenergic fibers within each nucleus which could be correlated with the distribution of vasopressin-containing neurons. In addition, through the combined use of immunofluorescence and retrograde transport of the tracer dye true blue, they were able to show that a small percentage of TH-containing neurons within the paraventricular nucleus project to the region of the dorsal motor vagal complex and/or thoracic levels of the spinal cord. Although the later finding relied upon fluorescence microscopy, Bowker a

Animals↗
PubMed1983

Organization and function of a central nervous system circadian oscillator: the suprachiasmatic hypothalamic nucleus.

Circadian rhythms in mammals are generated by endogenous neural oscillating systems entrained to the light-dark cycle by specific visual pathways. We conclude from available data that the suprachiasmatic hypothalamic nuclei (SCN) are the principal circadian oscillators in the rodent brain and that a retinohypothalamic projection terminating in the SCN is the primary visual pathway subserving entrainment of circadian rhythms. Recent anatomical studies demonstrate that the SCN have distinct subdivisions in the rat. A dorsomedial component is comprised of a distinct neuronal population and contains a large population of interneurons, many of which produce peptides. It receives no direct or indirect visual input and has only very limited projections outside the SCN. A ventrolateral component is also made up of a distinctive neuronal population, receives both direct and indirect visual projections, and provides the major external projections of the SCN, which are to the hypothalamus, particularly the hypophysiotrophic area. The SCN are viewed in this review as containing multiple, mutually coupled oscillating systems that arise from a developmental process of interconnecting individual neuronal circadian oscillators into circuits that form the oscillating systems. A model for the organization of the systems is presented.

Animals↗
PubMed1983

Circadian rhythms in rat brain neurotransmitter receptors.

In the rat brain there are daily rhythms in the number of alpha- and beta-adrenergic, muscarinic cholinergic, dopamine, opiate, and benzodiazepine receptors. The rhythms are circadian, i.e., with periods of approximately 24 h and endogenously generated. The characteristics of the circadian rhythms change over the year. Ablation of the suprachiasmatic nuclei, believed to act as a biological clock, abolishes the circadian rhythms. In the cerebral cortex the circadian rhythm in norepinephrine-stimulated cyclic AMP production is a biological response to the circadian rhythms in alpha- and beta-adrenergic receptors. The effects on neurotransmitter receptor rhythms of treatments that are antidepressant in humans were studied. Chronic administration of the antidepressant drugs imipramine and clorgyline delays the timing of the peak number of many receptors. Chronic administration of the antidepressant, antimanic drug lithium carbonate delays the timing of the peak number of some receptors and abolishes the rhythms in several others. Twenty-four hours of sleep deprivation is almost without effect on the rhythms. Fluphenazine and lithium, both antimanic in humans, increase the 24-h mean number of most receptors. Circadian receptor rhythms evoking intracellular circadian biological responses may modulate brain neurotransmission, coordinating internal physiological processes, and synchronizing them to environmental events. Alterations in circadian receptor rhythms with chronic psychoactive drug administration may play a role in the therapeutic actions of these drugs.

Animals↗
PubMed1982

Dopamine nerve terminal degeneration produced by high doses of methylamphetamine in the rat brain.

Numerous recent studies indicate that when amphetamines are administered continuously or in high doses, they exert long-lasting toxic effects on dopamine (DA) neurons in the central nervous system (CNS). Specifically, it has been shown that amphetamines can decrease the content of brain DA, reduce the number of synaptosomal DA uptake sites and selectively depress the in vitro activity of neostriatal tyrosine hydroxylase (TH). To date, however, anatomical evidence of DA neuronal destruction following amphetamines has not been reported. In this study, chemical methods were used in conjunction with the Fink-Heimer method which allows for the selective silver impregnation of degenerating nerve fibers, in order to determine whether methylamphetamine, a potent psychomotor stimulant often abused by man, causes actual DA neural degeneration. It has been found that methylamphetamine induces terminal degeneration along with correlative DA neurochemical deficits in the neostriatum and nucleus accumbens; furthermore, that in cresyl violet-stained sections of the substantia nigra (SN), pars compacta, and ventral tegmental area (VTA), there is no evidence of cell body loss in rats in which 50-60% of neostriatal DA terminals have been destroyed.

3,4-Dihydroxyphenylacetic Acid↗