Neurons with multiple messengers with special reference in neuroendocrine systems.
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Biomedical subjects
Publications and source records attributed to M Schalling.
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Rat brain and adrenal gland were analyzed by hybridization histochemistry using an RNA probe complementary to mRNA for tyrosine 3-hydroxylase (TyrOHase; tyrosine 3-monooxygenase, EC 1.14.16.2), by immunohistochemistry using TyrOHase antiserum, and by retrograde tracing using the fluorescent compound Fast blue. Cell bodies in the ventral mesencephalon contained mRNA for TyrOHase, and these cells were also TyrOHase immunoreactive. After injection of Fast blue into the striatum, such double-labeled cells in addition contained the retrograde tracer, showing that these cells send axonal projections to the injection site. These results show that hybridization histochemistry can be used to identify transmitter-specific neuron populations and that their projections can be established.
In situ hybridization techniques were used to analyse the distribution of cholecystokinin (CCK) mRNA in the lower brain stem, spinal cord and dorsal root ganglia of the rat and guinea pig, in comparison with that of mRNAs for calcitonin gene-related peptide (CGRP) and choline acetyltransferase. In the rat, CCK mRNA was found in numerous motoneurons in the spinal cord as well as in the motor trigeminal, facial and hypoglossal nuclei. Coexistence of CCK mRNA and CGRP mRNA could be established in spinal and brain stem motoneurons. Conversely, in the guinea pig CCK mRNA could only be detected in few motoneurons in the spinal cord. In both species, CCK mRNA was present in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord, in numerous small cells located in the outer laminae (mainly II-IV), and in the rat was also found in large cells in laminae IV and V. Few small cells in laminae VI-VIII and X of the spinal cord and cells in several brain stem nuclei, such as the solitary tract, gracile and cuneate nuclei, also showed CCK mRNA in the rat. In the guinea pig brain stem CCK mRNA was found, among others, in the solitary tract nucleus, pontine reticular formation and pontine periventricular grey. In dorsal root ganglia CCK mRNA was abundant in the guinea pig, but almost absent in the rat, where only single cells were found that expressed low levels of this mRNA.
In the present immunohistochemical study the occurrence and distribution of CCK-immunoreactive neurons were analyzed in the brain, spinal cord and sensory ganglia using sequence specific antisera. Thus, antibodies directed towards the C-terminal portion of CCK-33, to the N-terminal portion of CCK-8 and to the mid portion of CCK-33 as well as monoclonal antibodies were used. For comparison antisera raised against calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and 5-hydroxytryptamine (5-HT) were used. Untreated, colchicine treated, 6-hydroxydopamine (6-OH-DA) treated and ibotenic acid treated rats were analyzed. The results indicate that most CCK systems in the rat central nervous system contain genuine CCK. These include, for example, the hippocampal formation, the hypothalamus, several subcortical forebrain areas, the ventral mesencephalon, nucleus tractus solitarii, some neurons in the ventral medulla oblongata as well as local and possibly descending neurons in the spinal cord. An exception was primary sensory neurons in which CCK-like immunoreactivity (LI) could only be demonstrated with C-terminally directed antisera and probably represents cross-reactivity with CGRP or a similar peptide. The central branches of such primary afferents were found both in the dorsal vagal complex, in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord. Special attention was focused on CCK-LI in mesencephalic dopamine neurons and in their projection areas including nucleus accumbens, tuberculum olfactorium and particularly the caudate nucleus. In the latter structure CCK-LI exhibited a heterogenous pattern probably representing fibres of different types and origin. Thus, CCK-LI coexists with dopamine in two anatomically and morphologically distinguishable systems, one located in the periventricular area, increasing in size in the caudal direction to occupy most of the cauda, and a second system consisting of very fine dots in the medial half of the caudate nucleus. These two fibre types disappeared after 6-OH-DA treatment. A third system consisted of strongly fluorescent patches distributed at all levels of the caudate nucleus, mainly in its medial half. A diffuse, weakly fluorescent network of CCK-positive fibres was also found over the entire caudate nucleus. The latter two systems did not disappear after 6-OH-DA. Finally, local CCK-positive cell bodies were seen in small numbers, mainly in the ventral aspects of the caudate nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)
This paper discusses the gravity (of up to 2 g) effect on the upright stability of 16 test subjects exposed either to centrifugation or to artificially increased body weight (with uniformly distributed loading). During centrifugation the stabilographic parameters increased significantly at every gravity level. In the experiments with artificially increased body weight the area of the vector stabilograms also increased significantly. The comparison of the two experimental runs suggests that disorders in the upright stability are caused by the rotation factor rather than by the artificially increased body weight.