Search PubMed⌕ Search

Biomedical subjects

P Panula

Publications and source records attributed to P Panula.

At least 181 records · Page 10Linked to original sources
PubMed1984

Intrinsic GABAergic system of adrenal chromaffin cells.

Histochemical and biochemical studies demonstrate that gamma-aminobutyric acid (GABA), glutamic acid decarboxylase (EC 4.1.1.15), and GABA aminotransferase (EC 2.6.1.19) are present in bovine adrenal chromaffin cells. Moreover, [3H]GABA can be taken up and stored by primary cultures of adrenal chromaffin cells. Nicotinic receptor stimulation or KCl depolarization releases the [3H]GABA taken up by these cell cultures. GABA and benzodiazepine recognition sites located in chromaffin cells interact with each other with modalities similar to those described for GABA and benzodiazepine recognition sites located in synaptic membranes prepared from brain tissue. Bicuculline facilitates the release of catecholamine from chromaffin cells induced by nicotinic receptor stimulation but it fails to influence the release of catecholamine evoked by K+ depolarization. Since the GABA-benzodiazepine receptor system appears to modulate nicotinic receptor function, it is suggested that GABA transmission might participate in modulating responsiveness of chromaffin cells to incoming cholinergic stimuli.

4-Aminobutyrate Transaminase↗
PubMed1984

Histamine-containing neurons in the rat hypothalamus.

A specific antiserum against histamine was produced in rabbits, and an immunohistochemical study of histamine-containing cells was carried out in rat brain. The antiserum bound histamine in a standard radioimmunoassay and stained mast cells located in various rat and guinea pig tissues. Enterochromaffin-like cells in the stomach and neurons in the posterior hypothalamic area could be detected with this antiserum. The staining was highly specific and was not abolished by preabsorption with histidine, histidine-containing peptides, serotonin, or catecholamines, whereas preabsorption with histamine completely abolished the staining. Immunoglobulins of this antiserum purified by affinity chromatography stained the same cells as did the crude antiserum, whereas the serum fraction, which was not absorbed by histamine-affinity ligand, failed to stain any neuron. Histamine-immunoreactive neuronal cell bodies were found only in the hypothalamic and premammillary areas of colchicine-treated rats. The largest group of cells was seen in the caudal magnocellular nucleus and medially on the dorsal and ventral aspects of the ventral premammillary nucleus. Immunoreactive nerve fibers, but no cell bodies, were detected in other parts of the brain. Histamine-immunoreactive mast cells were found in the median eminence and pituitary gland. The results suggest that histamine-containing neurons are located only in a small area of the posterior hypothalamus, and these cells are probably the source of ascending and descending fibers detected in other brain areas.

Animals↗
PubMed1984

Bombesin/gastrin-releasing peptide (GRP)- and Met5-enkephalin-Arg6-Gly7-Leu8-like immunoreactivities in small intensely fluorescent (SIF) cells and nerve fibers of rat sympathetic ganglia.

Superior cervical and hypogastric ganglia were removed from rats that had been perfused with a mixture of 4% paraformaldehyde and 0.25% glutaraldehyde. Specific antisera against Met5-enkephalin-Arg6-Gly7-Leu8 (MEAGL) and bombesin/gastrin-releasing peptide (BN/GRP) were used in the immunofluorescence procedure. In hypogastric ganglia, a subpopulation of small intensely fluorescent (SIF) cells, as identified by their aqueous aldehyde (Faglu)-induced fluorescence, showed MEAGL- and BN/GRP-like immunolabeling. SIF cells in the superior cervical ganglia were unlabeled. In both ganglia, varicose nerve fiber networks and nerve terminals surrounding principal ganglion cells showed MEAGL- and BN/GRP-like immunoreactivities. Unlabeled SIF cells often were in close contact with nerve fibers that had MEAGL-like immunolabeling. Immunoreactivities against MEAGL- and BN/GRP-like neuropeptides in nerve fibers and terminals suggest a neurotransmitter or neuromodulator role for these peptides. In addition, labeling in SIF cells implies their possible endocrine function.

Animals↗
PubMed1984

Immunohistochemical evidence for preproenkephalin A synthesis in human retinoblastoma.

Human retinoblastoma contains clusters of cells immunoreactive for methionine-enkephalin and methionine-enkephalin-arginine-phenylalanine. Some tumour cells also exhibited methionine-enkephalin-arginine-glycine-leucine-like immunoreactivity. The results are in agreement with those obtained with similar testing of neuroblastoma cell cultures. It is concluded that some human retinoblastoma cells are capable of synthesizing preproenkephalin A or parts of this molecule.

Cells, Cultured↗
PubMed1983

The transsynaptic regulation of the septal-hippocampal cholinergic neurons.

There is not yet a complete understanding of the functional interactions among various septal nuclei which regulate hippocampal function. Nevertheless, much has been learned histologically and biochemically about the major connections of the distinct areas of the septal complex and the chemical character of some of these pathways. The cholinergic septal-hippocampal pathway serves as a well defined link between these two important structures of the limbic system. Acetylcholine turnover rates in the hippocampus have been shown to increase or decrease proportionally to the activity of the cholinergic neurons originating in the septum. Moreover, these turnover rates have been shown to be modulated by intraseptal injections of agonists or antagonists of various neurotransmitters or neuromodulators which are stored in various cell groups located in the septum. By coupling this biochemical approach with techniques to study the receptor organization, greater detail concerning the transmitter and cotransmitter interactions among the various neuromodulators can be obtained.

Acetylcholine↗
PubMed1983

Characterization and location of Met5-enkephalin-arg6-phe7 stored in various rat brain regions.

A specific antiserum against met5-enkephalin-arg6-phe7 was raised and used to study the distribution and characterization of met5-enkephalin-arg6-phe7-like immunoreactive material in rat brains by radioimmunoassay and immunohistochemical procedures. The antiserum appears to be directed to the COOH-terminus of the peptide, as it fails to cross-react with met5-enkephalin, met5-enkephalin-arg6, met5-enkephalin-arg6-arg7, met6-enkephalin-lys6, and leu-enkephalin. However, it cross-reacts with phe-met-arg-phe by about 10% and with phe-met-arg-phe-NH2 to an insignificant degree. The highest content of met5-enkephalin-arg6-phe7 was found in the striatum, which contains a dense network of immunoreactive varicose fibers and terminals, as well as immunoreactive cell bodies. The met5-enkephalin-arg6-phe7 in striatum can be released in a Ca2+-dependent manner by a depolarizing concentration of KCl, raising the possibility of a neuroregulatory role for met5-enkephalin-arg6-phe7. Characterization of the immunoreactive material by gel filtration and high pressure liquid chromatography revealed the presence of multiple forms of immunoreactive material in some brain regions.

Animals↗
PubMed1983

Immunohistochemical localization of bombesin/gastrin-releasing peptide and substance P in primary sensory neurons.

The existence of bombesin/gastrin-releasing peptide-like immunoreactivity (BN-GRP-LI) in rat sensory ganglia and spinal cord was confirmed using immunocytochemistry, gel filtration chromatography, and high performance liquid chromatography combined with radioimmunoassay. Immunohistochemical studies showed that in the spinal sensory ganglia of the rat about 5% of the neurons exhibited BN-GRP-LI, whereas about 20% of the neurons exhibited substance P-like immunoreactivity (SP-LI). The two immunoreactivities were found in different cells, but both were located in small ganglion cells. In the posterior horn of the spinal cord, BN-GRP-LI and SP-LI were located in the superficial layers, and this distribution was different from that of Met5-enkephalin-like immunoreactivity. The results are in agreement with the concept that there is a primary sensory pathway from the sensory ganglia to the spinal cord which contains BN-GRP-LI and that these neurons are separate from those containing substance P. In extracts prepared from spinal ganglia, two molecular weight forms of BN-GRP-LI were found using gel filtration chromatography. The high molecular weight form coeluted with porcine GRP and the low molecular weight form was smaller than bombesin. The low molecular weight BN-GRP-LI extracted from spinal cord was more hydrophilic than bombesin or ranatensin.

Animals↗
PubMed1982

The permeability alteration of brain and spinal cord vasculature to horseradish peroxidase during experimental decompression sickness as compared to the alteration in permeability induced by hyperosmolar solution.

The permeability of microvasculature in the cerebral cortex, neostriatum, and spinal cord to i.v. injected horseradish peroxidase (HRP) has been investigated in rats following experimental compression to 6.1 bars (abs.) air for 90 min, and subsequent decompression to the ambient pressure in 1 min. For comparison, 1 ml of 2.0 M urea was injected into the right common carotid artery of rats during 15 s. After exposure to compression-decompression, under the light microscope focal leaky areas were found in all the regions examined. The leakage was most prominent in the grey matter of the spinal cord, and the cerebral cortex. In decompressed rats, arterioles were most often the site of peroxidase extravasation, whereas extravasation of HRP was less frequently displayed by capillaries and venules. In urea-treated rats, capillaries and venules frequently displayed extravasation of HRP as well. Parenchymal cells accumulated the trace adjacent to the leaky areas. Under the electron microscope, the extravasation of HRP was associated with peroxidase-containing pleomorphic vesicular structures in the endothelium, both in decompressed and urea-injected rats. Moreover, in contrast to decompressed rats, the junctions between endothelial cells were penetrated by the trace in urea-treated rats. Accordingly, the results indicate that during decompression sickness the pathway for the extravasation of proteins is through vesicular transfer, whereas the injection of hyperosmolar urea induces extravasation, both through vesicular transfer and junctions between the endothelial cells.

Animals↗
PubMed1982

Neuronal location of the bombesin-like immunoreactivity in the central nervous system of the rat.

The immunohistochemical distribution of bombesin-like immunoreactivity in the central nervous system of the rat was revealed using a rabbit antibody against [Glu7]bombesin(6-14). In radioimmunoassay, the antibody had minimal cross reactivity with substance P thereby enhancing the significance of histochemical controls proving that the immunoreactivity detected was related to bombesin but not to substance P. Bombesin-immunoreactive neurons were detected in several brain structures including the hypothalamus, interpeduncular nucleus, central grey, dorsolateral tegmental nucleus, dorsal parabrachial nucleus, nucleus of the solitary tract and trigeminal complex. In the spinal cord, intense immunoreactivity was found in the superficial layers of the posterior horn. Since in this area the reaction diminished after rhizotomy the location of the peptide in afferent neurons was considered. In the anterior horn the bombesin-like immunoreactivity located in nerve terminal-like structures was unchanged after rhizotomy suggesting that the cell bodies were located in CNS.

Animals↗
PubMed1982

The resistance of glyoxylic acid induced catecholamine fluorescence to sodium borohydride reduction.

The borohydride reduction of glyoxylic acid induced fluorescence in noradrenergic and DOPA-minergic nervous structures and in amines in model experiments was studied. Both DOPAmine and noradrenaline fluorescences were resistant to borohydride reduction differing thus from the formaldehyde-induced fluorescence. Thus when the specificity of glyoxylic acid induced fluorescence is in doubt, other tests than borohydride reduction of the fluorescence must be employed.

Animals↗
PubMed1981

Ultrastructure of GABA-neurons in cultures of rat neostriatum.

The subcellular distribution of glutamate decarboxylase (GAD) was revealed by electron microscopic immunocytochemistry in primary cultures of the rat neostriatum. Immunoreactivity was restricted to a small nerve cell type with rich amounts of free ribosomes and an indented nucleus. Glial cells were non-reactive. The results indicate that GABA-synthesizing neurons are viable in culture conditions and suggest that neostriatal GABA-neurons are small cells with simple ultrastructure since larger cells did not possess immunoreactivity.

Animals↗
PubMed1980

Ultrastructural localization of acetylcholinesterase activity in primary cultures of rat substantia nigra.

Ultrastructural localization of acetylcholinesterase activity was studied in primary cultures of the substantia nigra microdissected from newborn rat brains. Light microscopic observations were also made on the characteristics of dopamine neurones and acetylcholinesterase containing cells in these cultures. Ultrastructurally acetylcholinesterase activity was localized in the nuclear envelope and rough endoplasmic reticulum of neurones, which had deeply infolded, round or oval nucleus, a prominent Golgi apparatus and varying amounts of rough endoplasmic reticulum. In the neuropil acetylcholinesterase activity was seen within microtubules of neuronal processes and in the rough endoplasmic reticulum of dendrites. The enzyme activity was also demonstrated within the nuclear envelope and rough endoplasmic reticulum of probably capillary endothelial cells. Dopaminergic neurones were identified on the basis of the green catecholamine fluorescence they exhibited. Small dopaminergic neurones could be observed and there was indirect evidence that these cells did not stain for acetylcholinesterase.

Acetylcholinesterase↗
PubMed1980

Demonstration of enkephalin-, substance P- and glutamate decarboxylase-like immunoreactivity in cultured cells derived from newborn rat neostriatum.

The presence of cells exhibiting leucine-enkephalin-, substance P- and glutamate decarboxylase-like immunoreactivity was demonstrated in dissociated cultures from newborn rat neostriatum. The size and shape of the enkephalin-immunoreactive cells varied, but they were generally larger than substance P- and glutamate decarboxylase-immunoreactive cells, which formed relatively uniform cell populations. Cells of apparently non-neuronal origin did not show any immunoreactivity. It is unlikely that enkephalin is present in the same cells that contain substance P or glutamate decarboxylase because of morphological differences between these cells. The possible coexistence of substance P and glutamate decarboxylase in the same cells however, could not be excluded. The results of this study confirm that the cell bodies of neurons containing three possible neurotransmitters are located in the neostriatum.

Animals↗
PubMed1979

Fluorescence histochemical observations on the distribution of exogenous dihydroisoquinoline in the rat brain.

The distribution of fluorescence in the rat brain after i.p. or intracerebral (i.c.) injections of a fluorescent dihydroisoquinoline derivate of dopamine was studied. After low i.p. doses (50 mg/kg of body weight) the fluorescence was totally confined to the capillary endothelial cells in the cerebral cortex, neostriatum, and substantia nigra (Sn). After large i.p. doses (500 mg/kg) fluorescent material was also present in the neuropil of all the regions studied and some cells of the cerebral cortex and SN. Ater injections to the neostriatum or SN fluorescence was observed in the endothelial cells and some small to medium-sized rounded cells in both regions. A conspicious dark area contrasting with the background fluorescence was constantly present around capillaries, and this area was in contact with nonfluorescent multibranched cells of astrocytic type. In fluorescent cells the fluorescence was present both in the cytoplasm and the nucleus.

Animals↗
PubMed1979

The development of histochemically demonstrable cholinesterases in the rat neostriatum in vivo and in vitro.

The development of acetylcholinesterase (AChE) and non-specific cholinesterase (NsChE) activity was studied in the rat neostriatum by the light and electron microscope using three thiocholine methods. The AChE activity was first demonstrable only in the lateral parts of the nucleus, and during the early postnatal development the most intense activity was in the cell bodies, whilst the typical intense staining of the neuropil of adult animals was seen in two-week-old rats. Two types of AChE-containing cells were observed in the neostriatum of rats younger than two weeks and in cultures of newborn rat neostriatal cells. The neuropil of the cultures showed weak activity in the membranes of thin preterminal processes. In the neuropil of old rats, NsChE activity was present in the membranes of nerve cell processes. The capillary endothelial cells of newborn rats contained both AChE and NsChE. During subsequent development, the AChE activity disappeared, whilst for NsChE no change was seen in the distribution of activity seen in newborn or young adult rats less than three months old.

Acetylcholinesterase↗