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Biomedical subjects

R Y Moore

Publications and source records attributed to R Y Moore.

At least 19 recordsLinked to original sources
PubMed1979

Pineal N-acetyltransferase and hydroxyindole-O-methyltransferase: control by the retinohypothalamic tract and the suprachiasmatic nucleus.

The visual pathway and central neural structures involved in the photic and endogenous regulation of the activity of pineal N-acetyltransferase and hydroxyindole-O-methyltransferase were investigated. The results indicate that the visual pathway regulating both enzymes is the retinohypothalamic tract, and that the inferior accessory optic tract is clearly not involved in the regulation of hydroxyindole-O-methyltransferase activity, as has been previously thought. In addition, the suprachiasmatic nucleus was found to be necessary for the generation of a rhythm in N-acetyltransferase activity in blinded animals, and to be responsible for the tonic elevation of hydroxyindole-O-methyltransferase activity in blinded animals. Finally, it was concluded that the rapid and large daily changes in N-acetyltransferase activity seen in a normal lighting cycle and the much slower and smaller changes in hydroxyindole-O-methyltransferase activity seen only after weeks in constant lighting conditions are mediated by the same neural tract; the different time courses of the effects of environmental lighting may be explained on the basis of different intracellular regulatory mechanisms.

Acetylserotonin O-Methyltransferase↗
PubMed1979

Retinohypothalamic tract development: alteration by suprachiasmatic lesions in the neonatal rat.

The suprachiasmatic nucleus (SCN), the terminal nucleus of the retinohypothalamic (RH) tract, was ablated electrolytically in 2-day-old rats. Since previous studies have demonstrated that the earliest retinal fibers arrive on postnatal day 3 to 4 (refs. 4, 17), the lesions were inflicted prior to the formation of retinal connections. At day 25, [3H]proline was injected into the eye and autoradiography performed to determine if developing RH fibers would exhibit plasticity and innervate any hypothalamic nucleus other than the SCN. No evidence was found for the formation of anomalous retinal connections after complete, bilateral SCN lesions. Incomplete lesions, however, result in some alteration in the distribution of retinal fibers to the SCN. If a part of the caudal three-quarters of the SCN remains, RH projections form in a pattern dependent upon the size and location of the intact SCN fragment. These results indicate a high degree of specificity in developing RH fibers for their normal target tissue and a minimal capacity for plasticity in contrast with the various forms of neuronal reorganization observed after early destruction of other components of the visual system.

Animals↗
PubMed1979

Neonatal suprachiasmatic nucleus lesions: effects on the development of circadian rhythms in the rat.

Previous studies of the effects of suprachiasmatic nucleus (SCN) destruction and visual pathway transections in adult rodents have revealed the primary significance of the SCN and the retinohypothalamic (RH) projection in the generation and entrainment of circadian rhythms. In the present study we found that complete ablation of the SCN in 2-day-old rats, prior to its innervation by the RH projection, permanently eliminates circadian rhythms in spontaneous locomotor activity and drinking; activity and drinking appear randomly distributed over the light-dark cycle. In addition, females exhibit long periods of constant vaginal cornification and an absence of normal estrous cycles. These effects are independent of the animal's visual status; that is, they occur in blinded as well as sighted animals. Incomplete SCN lesions results in partial disruption of rhythmic functions such as damping of circadian rhythms in activity and/or drinking, irregular estrous cycling, and/or complete disruption of only one or two of these measures of rhythmicity. The absence of spared functions after early SCN destruction is consistent with the high degree of specificity for the SCN exhibited by developing RH fibers and further emphasizes the significance of the SCN in circadian rhythm generation. Neither morphological nor functional plasticity has been found following neonatal ablation of the SCN in the rat.

Animals↗
PubMed1979

Development of the noradrenergic innervation of neocortex.

The development of the noradrenaline (NA)-neuron innervation of rat neocortex was studied by fluorescence histochemistry, high affinity uptake of [3H-]NA, and biochemical assay of regional NA content. Fluorescence histochemistry indicates that NA axons enter areas of developing neocortex prenatally and the innervation matures rapidly during early postnatal life. Frontal and lateral neocortical areas are the first to be innervated followed by occipital and parietal areas. All cortical layers receive innervation. The distribution and density of neocortical NA innervation achieves the adult pattern by the end of the first postnatal week. High affinity uptake studies confirm the observations from fluorescence histochemistry and show a very rapid maturation of the NA axon innervation with adult levels of uptake occurring by postnatal day 9. Following birth, there is a brief rise in NA content from PO to P2 in all neocortical areas. NA content then drops to low levels in all areas by P4. This is followed by a gradual increase in NA content in all areas occuring over several months. This pattern of development of NA axon innervation of neocortex demonstrates that the density and distribution of NA axons in developing neocortex matures much earlier than shown in previous studies whereas the NA content of the developing axonal plexus achieves adult levels later in postnatal life.

Adrenergic Fibers↗
PubMed1979

Dorsal thalamic lesion in a noted case of human memory dysfunction.

The extensively studied patient N.A. has had a severe verbal memory deficit since 1960, when he sustained a stab wound to the brain with a miniature fencing foil. His amnesia occurs in the absence of any other known cognitive defect. Recent CT scans have localized a lesion in the left dorsal thalamus of this patient in a position corresponding to the dorsomedial nucleus; there is no radiographic evidence of other damage in the diencephalon or cerebral cortex. The dorsomedial thalamus may be critical in the neuropathology of diencephalic amnesia and, in humans, may be required for normal memory functions.

Adult↗
PubMed1979

Ontogeny of the noradrenergic innervation of the rat hippocampal formation.

The noradrenergic (NA) innervation of the rat hippocampal formation arrives embryonically into a structure in which cytogenesis and cell migration are still active processes. At embryonic day 18 (E18) the first fluorescent axons appear in the septal end of CA3 at the boundary of the marginal zone and cortical plate, the future stratum lucidum. By birth axons invade the subiculum and also course along the septo-temporal axis in a longitudinal associational system in stratum moleculare of CA3. The innervation of the area dentata increases significantly by postnatal day four (P4). The innervation pattern throughout the dentate and Ammon's horn is fairly complete by P10. High affinity uptake of 3H-NA also matures embryonically and correlates postnatally with the extent of innervation estimated by fluorescence histochemistry. The levels of endogenous NA develop more slowly, showing only 60--80% of older adult values by P48. Compared to the maturation of other hippocampal afferents, the NA innervation is extremely precocious. It is localized in areas which could allow it to have significant trophic functions during early stages of histogenesis. In addition, its presence in the rapidly developing structure may contribute to its eventual distribution in a relatively less organized terminal pattern than that of the later-arriving entorhinal, commissural and septal afferents.

Animals↗
PubMed1979

Monoamine neuron regulation of LRF neurons innervating the organum vasculosum laminae terminalis and median eminence.

The LRF content of the median eminence (ME) and organum vasculosum laminae terminalis (OVLT) was analyzed following lesions destroying the serotonin neurons of the midbrain raphe and the dopamine neurons of the zona incerta. Six weeks after zona incerta lesions the LFT content of both OVLT and ME was significantly reduced. Raphe lesions did not significantly reduce LRF content of the ME or OVLT. No changes in circulating LH content were noted after either lesion. These observations suggest that the dopamine neurons of the incerto-hypothalamic system may be involved in the regulation of LRF synthesis or release from LRF neurons innervating the ME and OVLT.

Animals↗
PubMed1979

Superior colliculus efferents to the hypothalamus.

The projection of the superior colliculus to the hypothalamus was studied in the rabbit and rat with light and electron microscopic techniques. This projection system, as demonstrated with the anterograde transport of tritiated leucine, proline, adenosine or horseradish peroxidase, is primarily to dendrites located in the ipsilateral optic and supraoptic tracts. The dendrites originate from cells located in the lateral and anterior hypothalamic areas, retrochiasmatic area and supraoptic nucleus. Thus, the ventral tier of the hypothalamus appears to receive both separate and overlapping visual and multimodal sensory-motor inputs from the retina, ventral lateral geniculate nucleus and superior colliculus.

Adenosine↗
PubMed1979

Neonatal ablation of the suprachiasmatic nucleus. Effects on the development of the pituitary-gonadal axis in the female rat.

Ablation of the suprachiasmatic nucleus (SCN) at 2 days of age, prior to the formation of the retinohypothalamic projection, produces a permanent state of constant vaginal estrus in the postpubertal female rat. Although such lesions do not alter the onset of puberty in sighted rats, they do compensate for the delay in vaginal opening induced by neonatal binding. The ovaries of sighted and blinded SCN-lesion rats are small and polyfollicular and the pituitaries of blinded SCN-lesion rats are abnormally large. Sampling of plasma in the morning and afternoon for up to 12 consecutive days in sighted SCN-lesion rats reveals continuously low luteinizing hormone levels. This constellation of endocrine alterations does not correlate with damage to any structures outside the SCN. Since the organization of the rodent estrous cycle is circadian, these results emphasize further the importance of the SCN in circadian rhythm generation. The necessity of an intact SCN for the development of normal, cyclic reproductive function implies that sparing or recovery of function does not occur.

Animals↗
PubMed1978

Developmental organization of raphe serotonin neuron groups in the rat.

The pre- and early postnatal development of serotonin neurons in the rat brainstem was studied using the fluorescence histochemical method. The technique utilized does not require drug pretreatment to visualize an intense serotonin fluorophore localized in neuronal perikarya, dendrites, and axons. All the serotonin neuron groups develop as bilateral nuclei which extend from the midbrain through the medulla. Six of the nine groups undergo a midline fusion from embryonic day 18 (E 18) through postnatal day 6 (P 6) in a rostrocaudal gradient. Cells of the nucleus raphe dorsalis fuse first (by P 1), whereas the serotonin neurons located in nucleus raphe pallidus do not fuse until P 6. This gradient is comparable to the one described for the first observable fluorescence in the serotonin neurons groups. After final cell division, the serotonin neurons undergo a primary migration from the ventricular zone along the midline, where they are situated during embryogenesis, and a secondary migration extending into postnatal life which concludes with fusion in the midline. The bilateral origins of the serotonin cell groups are maintained in the adult. This is expressed by the apparent ipsilateral projections of some of the raphe neurons determined recently in our laboratory utilizing autoradiographic and horseradish peroxidase techniques.

Animals↗
PubMed1978

The islands of Calleja: organization and connections.

The islands of Calleja (IC) in the rate are composed of seven small groups of granule cells in the polymorph layer of the olfactory tubercle and one large group, the insula magna, which lies along the border between septum, nucleus accumbens and nucleus of the diagonal band. The cytoarchitecture and neuronal morphology of the IC and surrounding cells, studied using Nissl-stained and Golgi-Kopsch material, are described. In addition, the afferent and efferent connections of the IC were analyzed using fluorescence histochemistry, the autoradiographic tracing method, and the anterograde and retrograde horseradish peroxidase methods. Topographically organized projections to the IC from the dopamine-containing cells of the substantia nigra-ventral tegmental area are demonstrated by the glyoxylic acid fluorescence histochemical method and the autoradiographic tracing technique. Anterograde and retrograde horseradish peroxidase studies provide evidence for reciprocal, topographically organized interconnections between the IC and the septum, nucleus accumbens, amygdala and piriform cortex. These observations indicate that the IC constitute a unique population of granule cells, located in the olfactory tubercle, innervated by dopamine neurons of the mesencephalon and interconnected with olfactory and non-olfactory components of the basal forebrain.

Animals↗
PubMed1978

Serotonin neurons of the midbrain raphe: ascending projections.

The ascending projections of serotonin neurons of the midbrain raphe were analyzed in the rat using the autoradiographic tracing method. Axons of raphe serotonin neurons ascend in the ventral tegmental area and enter the medial forebrain bundle. A number of fibers leave the major group to ascend along the fasciculus retroflexus. Some fibers enter the habenula but the majority turn rostrally in the internal medullary lamina of the thalamus to innervate dorsal thalamus. Two additional large projections leave the medial forebrain bundle in the hypothalamus; the ansa peduncularis-ventral amygdaloid bundle system turns laterally through the internal capsule into the striatal complex, amygdala and the external capsule to reach lateral and posterior cortex, and another system of fibers turns medially to innervate medial hypothalamus and median eminence and form a contrelateral projection via the supraoptic commissures. Rostrally the major group in the medial forebrain bundle divides into several components: fibers entering the stria medullaris to terminate in thalamus; fibers entering the stria terminalis to terminate in the amygdala; fibers traversing the fornix to the hippocampus; fibers running through septum to enter the cingulum and terminate in dorsal and medial cortex and in hippocampus; fibers entering the external capsule to innervate rostral and lateral cortex; and fibers continuing forward in the medial olfactory stria to terminate in the anterior olfactory nucleus and olfactory bulb.

5,6-Dihydroxytryptamine↗
PubMed1978

Catecholamine innervation of the basal forebrain. II. Amygdala, suprarhinal cortex and entorhinal cortex.

The catecholamine (CA) innervation of the posterior basal forebrain, the amygdala, suprarhinal cortex and entorhinal cortex, was studied in the rat using biochemical assay and fluorescence histochemistry. The assay studies demonstrate a moderate norepinephrine (NE) content in the amygdala and entorhinal cortex with a lower value for the suprarhinal cortex. Following destruction of the locus coeruleus, the decrease in NE content of these basal forebrain structures indicates that their principal NE innervation is from locus coeruleus. An additional small NE input arises from the medullary NE neuron groups. Ablation of dopamine (DA) cell groups (substantia nigra-ventral tegmental area, SN-VTA) indicates that the DA input to the amygdala arises from the lateral VTA and medial half of the SN. Fluorescence histochemical studies using the glyoxylic acid-Vibratome technique demonstrate the presence of four distinct types of CA neuron terminal plexus in the posterior basal forebrain. These include two different DA fiber types arising in SN-VTA, small NE fibers with small varicosities arising in locus coeruleus and NE fibers with larger varicosities arising in other brainstem NE cell groups. The large NE fibers appear to enter the amygdala via the ansa peduncularis-ventral amygdaloid bundle to innervate the central and basolateral nucleus and the anterior amygdaloid area. The locus coeruleus NE fibers appear to enter the posterior basal forebrain via both the stria terminalis and ansa peduncularis-ventral amygdaloid bundle system to form a moderately dense innervation of the central and basolateral nuclei of the amygdala and a less dense innervation of the other areas. The DA neuron axons are concentrated in the central and basal nuclei and intercalated cell groups. Other areas receive a more diffuse DA input, with the exception of the moderately dense innervation of the suprarhinal cortex and DA "islands" in the ventral-anterrior entorhinal cortex, The DA input to the posterior basal forebrain is complex and heterogeneous and the axonal morphology differs greatly among the terminal fields within the amygdala and adjacent cortical areas.

Amygdala↗
PubMed1978

Catecholamine innervation of the basal forebrain. III. Olfactory bulb, anterior olfactory nuclei, olfactory tubercle and piriform cortex.

The catecholamine innervation of the olfactory bulb, anterior olfactory nuclei, olfactory tubercle and piriform cortex was studied in the rat using biochemical analysis and fluorescence histochemistry. Biochemical studies demonstrate a moderate norepinephrine (NE) content in all olfactory structures, a high dopamine (DA) content in the olfactory tubercle and a low DA content in the olfactory bulb, anterior olfactory nucleus and piriform cortex. Following locus coeruleus lesions NE content decreases 71% in the olfactory bulb, 82% in the anterior olfactory nucleus, 62% in olfactory tubercle and 77% in piriform cortex...

Amygdala↗
PubMed1978

Catecholamine innervation of the basal forebrain. IV. Topography of the dopamine projection to the basal forebrain and neostriatum.

In this study the location of dopamine (DA) neuron perikarya in the rostral mesencephalon of the rat was determined using the glyoxylic acid fluorescence histochemical technique. Subsequently the topography of the projection of these mesencephalic neurons on the basal forebrain and striatum was analyzed using the anterograde transport-autoradiographic tracing method and the retrograde transport-horseradish peroxidase (HRP) technique. The results of these anatomical studies were correlated with the biochemical and histochemical studies presented in previous reports (Moore, '78; Fallon and Moore, '78; Fallon et al., '78) to provide the following conclusions. The topography of the DA neuron projection of the basal forebrain and neostriatum is organized in three planes, dorsal-ventral, medial-lateral and anterior-posterior. DA cells are found almost exclusively in the substantia nigra (SN) and ventral tegmental area (VTA). Ventral cells of the SN and VTA project to the dorsal structures of the basal forebrain such as the septum, nucleus accumbens and neostriatum. The latter includes some DA cells located ventrally in the pars reticulata of the SN. Dorsal cells project to ventral structures. The medial-lateral topography is organized such that the medial sectors of the SN-VTA area project to the medial parts of nuclei in the basal forebrain and neostriatum whereas lateral sectors of the SN-VTA area project to the lateral parts of nuclei in the basal forebrain and neostriatum. An anterior-posterior topography also is evident such that anterior parts of the SN-VTA project anteriorly whereas the posterior SN-VTA projects more posteriorly in these areas. These observations are consistent with the view that the DA neurons of the SN-VTA complex form a single nuclear group with a highly topographically organized projection innervating not only deep nuclei of the telencephalon but allocortical structures as well.

Amygdala↗