Experimental alcoholic neuropathy in the rat: histological and electrophysiological study on the myoneural junctions and the peripheral nerves.
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Acetylcholinesterase↗
Biomedical subjects
P Panula
Publications and source records attributed to P Panula.
Age-dependent increase in the non-specific cholinesterase activity of the capillaries in the rat neostriatum.
Histochemically demonstrable non-specific cholinesterase activity in the capillaries of the neostriatum of 3-5-month-old rats was much weaker than that of 24-27-month-old rats. In the young adult rats the activity was electron microscopically localized mainly in endoplasmic reticulum and perinuclear cisternae of the endothelial cells, while capillaries of old rats showed a positive reaction also in the basal lamina and outer cell membranes of glial processes.
Aging↗
Evidence for the presence of viable endothelial cells in cultures derived from dissociated rat brain.
The morphology and histochemistry of dissociated newborn rat brain was studied in tissue culture. Direct microscopy of developing cells, electron microscopy and the alkaline phosphatase activity were used to identify the capillary endothelial cells.
Alkaline Phosphatase↗
Distribution of catecholamines and acetylcholinesterase activity in the same cryotome section of rat's neostriatum.
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Acetylcholinesterase↗
Immunocytochemical colocalization of histamine, histidine decarboxylase, 5-hydroxytryptamine and tyrosine hydroxylase in the superior cervical ganglion of the rat.
The coexistence of histamine, histidine decarboxylase (the enzyme synthesizing histamine), 5-hydroxytryptamine and tyrosine hydroxylase (the rate-limiting enzyme in catecholamine synthesis), was studied in the rat superior cervical ganglion with the indirect immunofluorescence method. Possible colocalization was examined by staining consecutive sections with two different antibodies, or alternatively in the same section by eluting the first antibody with a mild solution containing potassium permanganate and sulphuric acid, and by staining the same section with another antibody. It was shown that tyrosine hydroxylase immunoreactivity was found both in large principal nerve cells and in small cells, which on the basis of their size and high nucleus-cytoplasm ratio corresponded to small intensely fluorescent (SIF) cells. Histamine, histidine decarboxylase and 5-hydroxytryptamine immunoreactivities were observed only in SIF cells. Those SIF cells which were immunoreactive for histamine, histidine decarboxylase or 5-hydroxytryptamine also contained tyrosine hydroxylase immunoreactivity. On the other hand, all tyrosine hydroxylase-immunoreactive SIF cells were also immunoreactive for histidine decarboxylase or 5-hydroxytryptamine. Some of the SIF cells, which were non-reactive for histamine, were immunoreactive for tyrosine hydroxylase.
Animals↗
Neuropeptide FF, a mammalian neuropeptide with multiple functions.
Neuropeptide FF (NPFF) and neuropeptide AF (NPAF) are two mammalian amidated neuropeptides which are highly concentrated in the posterior pituitary, spinal cord, hypothalamus and medulla. One precursor protein has been identified in mouse, rat, bovine and human brain. The precursor contains a single copy of both peptides, followed by a glycine residues necessary for amidation and flanked by basic residues necessary for processing by enzymes. In the brain, NPFF-like immunoreactive neurons are found in the hypothalamus and medulla. These systems may be associated with observed effects of NPFF on memory and autonomic regulation, respectively. A hypothalamo-pituitary pathway may be involved in neuroendocrine regulation. This is supported by lack of NPFF in the pituitary gland of vasopressin-deficient Brattleboro rats. It is also possible that NPFF acts as a hormone, as it has been detected in human plasma. The spinal cord contains an intrinsic NPFF-ir neuron system, with cell bodies in the dorsal horn and around the central canal. Nerve terminals are highly concentrated in the superficial laminae of the dorsal horn, where NPFF-immunoreactivity can be released by, e.g., potassium and substance P. One specific high-affinity binding site, distinct from binding sites for other peptides, has been characterized in the rat and human brain and spinal cord. The NPFF receptor appears to be coupled to a G-protein, but details of the second messenger systems have not been clarified yet. Intracerebroventricular injection of NPFF induces a vigorous abstinence syndrome in morphine-tolerant rats. Although clear antiopioid-like effects of NPFF on pain have been observed, some studies have also demonstrated long-lasting analgesic effects. These findings and the observed increase in NPFF-immunoreactivity in the cerebrospinal fluid during development of opiate tolerance render NPFF an interesting and challenging target of investigation.
Amino Acid Sequence↗
The distribution of pituitary adenylate cyclase-activating polypeptide-like immunoreactivity is distinct from helodermin- and helospectin-like immunoreactivities in the rat brain.
Pituitary adenylate cyclase-activating polypeptide (PACAP) is an amidated 38-residue polypeptide isolated from the ovine hypothalamus. Helodermin, a 35-amino acid peptide, and helospectins, peptides of 38 and 37 amino acid residues, have been isolated from lizard venom. PACAP, helodermin and helospectins share structural features and have a similar profile of pharmacological effects: they stimulate adenylate cyclase. We studied the distribution and characteristics of PACAP-like immunoreactivity in the rat brain with immunochemical and immunohistochemical methods and compared its distribution with that of helodermin- and helospectin-like immunoreactivities. With radioimmunoassay, the highest concentrations of PACAP-like immunoreactivity were found in the hypothalamus and cerebellum. PACAP-immunoreactive cell bodies were located immunohistochemically in the supraoptic nucleus, paraventricular and periventricular hypothalamic nuclei, and in the central grey. PACAP-immunoreactive fibres and terminals were detected in the medial part of the central nucleus of amygdala, in the median eminence and neurohypophysis, and in the central grey. No PACAP-immunoreactive structures were observed in areas such as the cerebral cortex, hippocampus, or cerebellum. The distribution of PACAP-like immunoreactivity differed considerably from the distribution of helodermin- and helospectin-like immunoreactivities. The results of this study suggest that PACAP is a neuropeptide with a role in the regulation of endocrine function in the hypothalamo-hypophyseal axis.
Animals↗
Immunohistochemical demonstration of neuroactive substances in the inner ear of rat and guinea pig.
The presence and localization of different neuropeptides and other putative neurotransmitters or -modulators were examined by immunohistochemistry in the cochleovestibular end organs and in neurons innervating them in rats and guinea pigs. In the organ of Corti neural elements beneath inner hair cells showed immunoreactivity for enkephalin (ENK), calcitonin gene-related peptide (CGRP), L-glutamate decarboxylase (GAD), substance P (SP) and tyrosine hydroxylase (TH). Nerve chalices of type I vestibular hair cells contained SP and GAD, but not consistently. SP was only occasionally observed in neuronal cell bodies of the 8th cranial nerve but fine fibers with different neuroactive substances were seen in the nerve trunk in the following relative numbers: TH greater than SP greater than CGRP greater than ENK. The present data demonstrate the presence of several different neuroactive substances in the rat and guinea pig inner ear suggesting a multiplicity of neurotransmitters or -modulators in this system.
Animals↗
ECL cell morphology.
Using immunohistochemistry at the conventional light, confocal and electron microscopic levels, we have demonstrated that rat stomach ECL cells store histamine and pancreastatin in granules and secretory vesicles, while histidine decarboxylase occurs in the cytosol. Furthermore the ECL cells display immunoreactivity for vesicular monoamine transporter type 2 (VMAT-2), synaptophysin, synaptotagmin III, vesicle-associated membrane protein-2, cysteine string protein, synaptosomal-associated protein of 25 kDa, syntaxin and Munc-18. Using electron microscopy in combination with stereological methods, we have evidence to suggest the existence of both an exocytotic and a crinophagic pathway in the ECL cells. The process of exocytosis in the ECL cells seems to involve a class of proteins that promote or participate in the fusion between the granule/vesicle membrane and the plasma membrane. The granules take up histamine by VMAT-2 from the cytosol during transport from the Golgi zone to the more peripheral parts of the cells. As a result, they turn into secretory vesicles. As a consequence of stimulation (e.g., by gastrin), the secretory vesicles fuse with the cell membrane to release their contents by exocytosis. The crinophagic pathway was studied in hypergastrinemic rats. In the ECL cells of such animals, the secretory vesicles were found to fuse not only with the cell membrane but also with each other to form vacuoles. Subsequent lysosomal degradation of the vacuoles and their contents resulted in the development of lipofuscin bodies.
Animals↗