Biomedical subjects

P Panula

Publications and source records attributed to P Panula.

At least 109 records · Page 6Linked to original sources

PubMed1991

Fall in intracellular pH mediated by GABAA receptors in cultured rat astrocytes.

The influence of muscimol (a specific gamma-aminobutyric acid-A (GABAA) receptor agonist) on intracellular pH (pHi) was studied in cultured rat astrocytes by means of fluorescence spectrophotometry with BCECF as the H+ indicator. In an HCO3(-)-free medium, muscimol had little effect on pHi. In a solution containing 22 mM HCO3-, muscimol produced a reversible, concentration-dependent fall in pHi with a maximum of about 0.1-0.15 units. The muscimol-induced fall in pHi was antagonized by an increase in the external K+ concentration, which suggest that the acidosis is an immediate consequence of a net efflux of HCO3- through GABAA receptor channels rather than an indirect effect caused by a change in membrane potential. The present results raise the possibility that astrocytes may participate in the regulation of extracellular pH at GABAergic synapses and contribute to activity-induced pH changes in nervous tissue.

Animals↗

PubMed1991

Origin and distribution of neuropeptide-FF-like immunoreactivity in the spinal cord of rats.

Neuropeptide FF, or F8Famide (Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2; "morphine-modulating peptide"), isolated from bovine brain, is an FMRF-NH2-like peptide with morphine-modulating effects. Neuropeptide FF (NFF) is highly concentrated in spinal cords of various mammalian species. There is evidence that NFF participates in the modulation of nociceptive mechanisms. The present study was aimed at describing the distribution and origin of the neuropeptide-FF-like immunoreactivity (LI) in the rat spinal cord. For distribution studies spinal cord sections from colchicine-treated animals were processed according to the indirect immunofluorescence method. Retrograde fluorescent tracer was injected in the lumbar dorsal spinal cord to study descending NFF-LI-containing spinal pathways. NFF-immunoreactive (ir) cell bodies were detected in the substantia gelatinosa, marginal zone, laminae III, IV, and X at all levels of the spinal cord, and the dorsolateral funiculus, and dorsal gray commissure of the lumbosacral transition zone. NFF-ir fibers and terminals were identified in laminae I-IV and X, dorsolateral funiculus, intermediolateral cell column, dorsal gray commissure, sacral parasympathetic nucleus, and ventral horn. A spinal NFF-LI-containing descending pathway originating in the lamina X neurons was observed, but a supraspinal origin of descending NFF-ir fibers was not identified. According to this study the NFF-LI of the spinal cord is of intrinsic spinal origin. The anatomical distribution supports the concept that the NFF-like peptides have a role in the nociception. They may also be involved in sensory-visceral reflex arcs.

Amino Acid Sequence↗

PubMed1991

Ontogeny of the F8Famide-like (morphine-modulating) peptides in the central nervous system of rats.

FLFQPQRF-NH2 (F8Famide; FMRFamide-like peptide; morphine-modulating peptide) is a peptide isolated from bovine brain. It has some opiate analgesia modulating effects. In an adult rat central nervous system, F8Famide-like immunoreactivity is found in high concentrations in the posterior pituitary, hypothalamus, pons, medulla, and dorsal spinal cord. By using immunohistochemistry and radioimmunoassay, we studied the development of the F8Famide-immunoreactive system in the rat central nervous system during the ontogeny. F8Famide-immoreactive fibers and terminals first appeared in the median eminence on the twentieth embryonal day. Postnatally the F8Famide-immunoreactive system developed rapidly both in the brain and spinal cord, the immunoreactive structures having an adultlike distribution by the age of 1 week. A transient increase of the F8Famide-immunoreactive material was observed during the third and fourth postnatal weeks. By the age of 4 weeks, the F8Famide-containing neuronal system was adultlike both in distribution and quantity. The results suggest that the F8Famide-like peptides may act as neurotransmitters or neuromodulators from the time of their appearance in the brain and spinal cord. The early appearance and the distribution of the F8Famide-like immunoreactivity suggest that these peptides may participate, in addition to nociceptive mechanisms, in the regulation of blood pressure, feeding behaviour, and endocrine functions.

Amino Acid Sequence↗

PubMed1991

Association between histamine-containing mast cells and sensory nerves in the skin and airways of control and capsaicin-treated pigs.

The association between mast cells (visualized by routine staining and immunohistochemistry for histamine) and capsaicin-sensitive nerves (containing calcitonin gene-related peptide (CGRP) and substance P (SP] was studied in the pig. In the 1-ethyl-3(3-diethylaminopropyl)carbodiimide (EDCDI)-fixed skin tissue, histamine-containing mast cells and CGRP/SP-positive nerves were found in close association around blood vessels. In the EDCDI-fixed airway mucosa, only single histamine-containing mast cells were detected. However, many alcian blue-positive mast cells were found, sometimes close to the airway epithelium where CGRP SP-containing nerve were abundant. The CGRP/SP-containing nerve fibres were absent 2 days after systemic capsaicin pretreatment, but no changes in the number and distribution of tissue mast cells, granulocytes or lymphocytes, or the number of blood leukocytes were detected. Local injection of allergen, histamine and capsaicin into the skin of pigs actively sensitized with ascaris antigen caused a rapid light red-flare (vasodilation) reaction. Allergen and histamine, but not capsaicin, also produced plasma protein extravasation. In contrast to the absent flare, the protein extravasation response still occurred in capsaicin-treated pigs. The sensitivity to ascaris antigen was mediated by an IgE-like antibody. We conclude that a functional and morphological relationship exists between histamine-containing mast cells and capsaicin-sensitive sensory nerves in the pig skin. Mast cells and sensory nerves are also found in the airway mucosa and appear to be closely associated with the epithelium.

Animals↗

PubMed1991

Kainic acid-induced changes in histamine-immunoreactive nerve fibers in the rat brain.

Histamine is found in neurons and their long projections in the mammalian brain. The mammalian histaminergic system consists of nerve cell bodies in the tuberomammillary nucleus, and extensive, crossing projections to various brain areas. In addition to the tuberomammillary histaminergic system, histamine is found in rhombencephalic neurons during fetal development of rat. To investigate if histamine has a function in growth and regeneration of the nervous system, small injections of kainic acid were made into different parts of the rat brain. Histamine-immunoreactive nerve fibers were seen in and around the lesions 2 to 15 weeks after the injection. The density of these fibers was higher than that of the control side. The results suggest that histamine is either accumulated in pre-existing fibers or that sprouting of histamine-containing nerves is induced by the lesions. The newly established in situ hybridization method for the enzyme histidine decarboxylase may reveal possible dynamic changes in enzyme regulation associated with the lesions.

Animals↗

PubMed1991

Neurofibrillary tangles and histamine-containing neurons in Alzheimer hypothalamus.

The location of histamine-immunoreactive (IR) cell bodies in normal aged human brain and in cases of Alzheimer's disease (AD) were compared to the distribution of neurofibrillary tangles (NFT). Cryostat sections were fixed with carbodiimide and processed for histamine-immunohistochemistry using the PAP technique. NFT were visualized in the same sections using thioflavin. Histamine-IR cell bodies in human brain were concentrated in the tuberomammillary (TM) nucleus that embodied a major part of the hypothalamus. Although located in similar large profiles and mainly concentrated in the TM area, the numerous hypothalamic NFT in AD were seldom found within the histamine-IR neurons.

Aged↗

PubMed1991

Histamine and tyrosine hydroxylase in developing rat brain.

The distribution of histamine and tyrosine hydroxylase in fetal rat brain was investigated immunocytochemically in order to determine possible colocalization of these two substances. Embryonic rat brains were fixed with carbodiimide and processed for immunofluorescence studies with antisera against histamine and tyrosine hydroxylase either in the same sections or in consecutive sections. Histamine and tyrosine hydroxylase showed no colocalisation in the developing rat brain. However, fibre networks immunoreactive for histamine and tyrosine hydroxylase were often found in the same areas. The results of the study suggest that the catecholaminergic and histaminergic neurones develop separately in the rat brain. Based on the location of developing histamine-immunoreactive neurones, a more intimate relationship between histamine- and serotonin-containing neurones in the developing rat brain is plausible.

Animals↗

PubMed1991

Distribution of histamine in the developing peripheral nervous system.

The presence and ontogenetic distribution of histamine was studied in the developing peripheral nervous system of the rat by using an indirect immunofluorescence technique and a specific rabbit anti-histamine antiserum. Histamine immunoreactivity (IR) first appeared in peripheral nerves on embryonic day 14. The number and intensity of histamine-immunoreactive nerves was highest on embryonic days 16-18. During development starting from embryonic day 14, motoneurones in ventral horns of the spinal cord at cervical, thoracic and lumbar levels contained histamine IR. A subpopulation of sensory neurones in dorsal root ganglia exhibited histamine IR. Histamine IR was also present in nerve fibres of ventral and dorsal roots of spinal cord, as well as in spinal nerves. Population of neurons and nerve fibres in sympathetic and pelvic ganglia as well as in myenteric ganglia of the intestine were also labelled with the histamine antiserum. In peripheral target organs, histamine IR was observed in nerve fibres around bronchi of the lungs, in the atria of the heart, in the adrenal gland, in the intestinal wall, in muscular tissues and in subepithelial tissue of the skin. The results of this study indicate that histamine is widely distributed in different types of neurons and nerve fibers of the developing peripheral nervous system.

Animals↗

PubMed1991

Histamine in the nervous system of Macoma balthica (Bivalvia).

The distribution of histamine(HA)-immunoreactivity of the molluscan species Macoma balthica was mapped with an antiserum against a histamine-protein conjugate. The main ganglia of the central nervous system of M. balthica, the cerebropleural ganglia, the pedal ganglion and the visceral ganglion all contained strongly HA-positive fluorescent cell bodies. The positive cell bodies were situated in clusters in the outer region of the ganglia. Immunoreactive fibres were located in the inner neuropil region of the ganglia. Also the commissure and the connectives of the ganglia as well as many nerve roots contained HA-positive fibres. These results agree well with the recent finding of the wide distribution of histamine in the nervous system of two marine gastropod molluscs, Aplysia and Pleurobranchaea supporting the thought that histamine has an important role in many physiological function of molluscs.

Animals↗

PubMed1991

Histamine in the developing sympathoadrenal system.

The ontogenetic distribution of histamine in correlation with catecholamines in the developing rat sympathoadrenal system was analyzed by using an indirect immunohistochemical method and a specific rabbit anti-histamine antiserum. Tyrosine hydroxylase (TH) immunoreactivity was used as a marker of catecholamine synthesis. TH immunoreactivity appeared in retroperitoneal sympathetic tissues on embryonic day 12.5 (E 12.5) when it was found in cells of lumbar chain ganglia. In preaortic sympathetic tissue. TH immunoreactivity was observed on day E 13.5 and in adrenal medullae on day E 14.5. Histamine immunoreactivity was expressed in all of these tissues beginning from day E 14.5. First it was found mainly in nerve fibers, but also in some cells. During the embryonic development the number of histamine-immunoreactive cells increased in all sympathetic tissues studied. In newborn rats, histamine immunoreactivity was restricted to a subpopulation of sympathetic cells, i.e. small intensely fluorescent (SIF) cells of sympathetic ganglia, paraganglion-type cells and some adrenaline-synthesizing cells of the adrenal medulla.

Adrenal Glands↗

PubMed1991

Distribution of histamine in developing rat tissues.

An antiserum against conjugated histamine was used to reveal the location and time of the appearance of the amine in different organs during the development of fetal and early postnatal rats. Tissues were fixed in 4% 1-ethyl-3(3-dimethyl-aminopropyl) carbodiimide and standard indirect immunofluorescence technique was used. Histamine-immunoreactivity (HA-ir) was first detected in the rat fetus on the 10th embryonic day (day E10) in the embryonic liver. The liver remained immunoreactive during the second half of the fetal life. In addition to some small HA-ir cells in the stomach wall and in the kidneys on day E16, the papillary muscles of the fetal heart also exhibited patchy immunofluorescence at this stage. On day E18, HA-ir cells appeared in many other organs including lungs, gastric mucosa and smooth muscle cells of the stomach wall, heart muscle and subcutaneous tissue. The distribution of HA-ir in fetal tissues was most extensive on day E20 when the kidney tubules and the skin also exhibited bright fluorescence. These results suggest that histamine is widely distributed during fetal development in different cell types.

Animals↗

PubMed1991

Histamine neurons in human hypothalamus: anatomy in normal and Alzheimer diseased brains.

The anatomy of histamine-immunoreactive cell bodies in normal adult human brain was examined in detail. In addition, the distribution of these cells in three cases of Alzheimer's disease was compared to the distribution of neurofibrillary tangles. Histamine-immunoreactive cell bodies were confined to the tuberal and posterior hypothalamus, forming the tuberomammillary nuclear complex. Most of the about 64,000 histamine neurons were large and multipolar. They comprised four distinct parts: (i) a major ventral part corresponding to the classical tuberomammillary nucleus, (ii) a medial part including the supramammillary nucleus and part of the posterior hypothalamic area, (iii) a caudal paramammillary part, and (iv) a minor lateral part. The parts showed some similarity with the subgroups in rat. In human, as compared to rat, the histamine neurons occupy a larger proportion of the hypothalamus. Numerous neurofibrillary tangles were found in the Alzheimer hypothalami, concentrated in the tuberomammillary area. Most of them were of globular type and extracellular, and only a minority were histamine immunoreactive. They may represent remnants of degenerated tuberomammillary neurons.

Alzheimer Disease↗

PubMed1991

Central neuronal pathways containing FLFQPQRFamide-like (morphine-modulating) peptides in the rat brain.

Octapeptide FLFQPQRFamide (FMRFamide-like peptide; morphine-modulating peptide), isolated from bovine brain, has some opiate analgesia modulating effects. Octapeptide FLFQPQRFamide-like immunoreactivity is found in high concentrations in the posterior pituitary, hypothalamus, pons-medulla, and dorsal spinal cord. Octapeptide FLFQPQRFamide-immunoreactive neurons of the brain are localized in the medial hypothalamus and in the nucleus of the solitary tract. High densities of octapeptide FLFQPQRFamide-immunoreactive nerve terminals are found in the median eminence, lateral parabrachial nucleus, and nucleus of the solitary tract. By using the retrograde tract tracing method combined with immunohistochemistry, we studied the central pathways interconnecting the octapeptide FLFQPQRFamide-immunoreactive structures. The octapeptide FLFQPQRFamide-immunoreactive neurons of the hypothalamus sent projections bilaterally to the nucleus of the solitary tract. The octapeptide FLFQPQRFamide-immunoreactive neurons of the nucleus of the solitary tract projected to the contralateral side of the same nucleus, to the lateral parabrachial nuclei bilaterally, and to the ipsilateral periambigual region. The results give neuroanatomical evidence of interacerebral pathways containing recently identified FLFQPQRFamide-like peptides, which may belong to a larger family of peptides. These neuroanatomical findings support the previous pharmacological studies, suggesting that the mammalian FMRFamide-like peptides may, in addition to modulatory effects on nociceptive mechanisms, participate in the regulation of blood pressure, feeding behaviour and endocrine functions.

Amino Acid Sequence↗

PubMed1990

The distribution of histidine decarboxylase mRNA in the rat brain: an in situ hybridization study using synthetic oligonucleotide probes.

L-Histidine decarboxylase catalyzes the formation of histamine from the amino acid L-histidine. We have studied the distribution of neurons expressing mRNA for histidine decarboxylase in adult rat brain using in situ hybridization with synthetic oligonucleotide probes. The expression of mRNA for histidine decarboxylase was detected in the hypothalamic tuberomammillary nucleus that has been shown to contain histidine decarboxylase-like and histamine-like immunoreactivity, but not in any other brain area. This method may prove useful in studying the physiological role of central histaminergic neurons.

Animals↗

PubMed1990

Comparative study of histamine immunoreactivity in nervous systems of Aplysia and Pleurobranchaea.

The distribution of histamine in the nervous system of the marine molluscs Aplysia californica and Pleurobranchaea californica was studied by using a newly available immunohistochemical localization technique and specific antiserum against histamine-protein conjugate. We examined several sets of complete histological sections through the major ganglia of both animals, as well as all nerve roots of the buccal and cerebral ganglia and the corresponding target tissues. The results indicate that histamine is present in several neurons and/or nerve fibers of all major ganglia. An especially dense histamine fiber network in the buccal ganglion of both species suggests a major role for histamine in regulation of buccal-oral behaviors. Histamine was also observed in several identified nerve roots of the buccal and cerebral ganglia, as well as in the corresponding target tissues. Its localization in the Aplysia radular sac and in the statocyst neurons of both species suggest a role for histamine in sensory functions. Our study revealed many previously unknown histamine cells or cell clusters, some of which may be identifiable by electrophysiological methods. The findings also point to possible reinterpretation of previous findings, indicating that histamine may be a cotransmitter in identified cells, whereas the methodology itself suggests that special precautions must be taken to avoid spurious interpretations of specificity. As has now been observed in studies of serotonergic immunohistochemistry and in our own findings on VIP, histamine terminals were observed to lie in close contact with somata and axon hillocks, all of which suggest that axo-somatic connections in molluscs may be more prevalent than previously considered.

Animals↗

PubMed1990

Histaminelike immunoreactive neurons innervating putative neurohaemal areas and central neuropil in the thoraco-abdominal ganglia of the flies Drosophila and Calliphora.

The fused thoraco-abdominal ganglia of the flies Calliphora vomitoria and Drosophila melanogaster were investigated immunocytochemically with antisera against histamine. In both insect species, 18 histaminelike immunoreactive (HA-IR) neurons were resolved in these ganglia. Six of these neurons have cell bodies in the thoracic neuromeres and 12 in the fused abdominal neuromeres. All cell bodies are situated ventrally. In Calliphora all cell bodies are arranged in a segmental pattern. In Drosophila only the thoracic cell bodies have a segmental arrangement, whereas the abdominal ones are clustered anteriorly close to the last thoracic neuromere. In both species the six thoracic neurons supply processes to the synaptic neuropil in the thoracic neuromeres and to the dorsal neural sheath. The processes in the neural sheath run anteriorly in the lateral portions of the ganglion into the cervical connective. In a few regions laterally arborizing terminals are found in putative neurohaemal areas. These areas were investigated by electron microscopic immunocytochemistry in Calliphora. The HA-IR terminals (containing small granular vesicles) were found outside the "blood-brain barrier" below the acellular basal lamina of the neural sheath. Release of histamine into the circulation is therefore theoretically possible. The central processes of the six thoracic HA-IR neurons may interact synaptically with large numbers of other neurons in the neuropil, and the peripheral varicose fibers from the same HA-IR neurons possibly are neurohaemal release sites. The abdominal HA-IR neurons, in contrast, form extensive arborizations within the synaptic neuropil only. Both thoracic and abdominal neurons have ipsilateral and contralateral branches as well as processes that invade more than one neuromere. A single HA-IR neuron thus invades large volumes of synaptic neuropil. Histamine may be used by neurons of the ventral ganglia both as neurotransmitter (or neuromodulator) and as a circulating neurohormone released from the neural sheath.

Animals↗

PubMed1990

Organization of the histaminergic system in the brain of the turtle Chinemys reevesii.

To accumulate phylogenetic information on the central histaminergic system, we investigated the histaminergic system in the brain of the Reeves turtle, Chinemys reevesii, using the indirect immunofluorescent method with antiserum against histamine. Histaminergic neuronal cell bodies were found exclusively in the posterior part of the ventral hypothalamus. Histaminergic varicose fibers innervated almost all parts of the turtle brain, but tended to be concentrated in several areas. Very dense innervation was observed in the medial part of the telencephalon, ventrolateral part of the hypothalamus, nucleus habenularis lateralis, and ventromedial part of the tegmentum. Medium density of innervation was seen in the olfactory bulb, nucleus medialis amygdalae, and tectum. Only a few fibers were detected in the lateral part of the telencephalon, dorsal part of the hypothalamus, thalamus, rhombencephalon, and spinal cord. The main ascending fibers were observed in the lateral part of the hypothalamus, sending dense fiber bundles to the cortices dorsomedialis and medialis and nucleus habenularis lateralis. Descending fibers appeared to run in the ventral tegmental area, passing through the dorsal and ventral parts of the midline of the brain stem to the spinal cord. These findings indicate that the general morphological features of the histaminergic system in the turtle brain are similar to those in the mammalian and frog brains.

Animals↗

PubMed1990

Comparative neuroanatomy of the histaminergic system in the brain of the frog Xenopus laevis.

The distribution of the histaminergic neuronal system in the brain of the clawed frog Xenopus laevis was mapped with an antiserum against carbodiimide-fixed histamine and compared to that in mammals. The histamine-immunoreactive cell bodies were located in a small area of the posterolateral hypothalamus, close to the dorsal infundibular nucleus, which contains catecholaminergic and serotonergic neurons. This area may be homologous to the tuberomammillary nucleus in mammals. A thick process extended from each cell between the ependymal cell layer and terminated in the ventricle lumen. The number of histaminergic cell bodies in adult Xenopus brain was relatively low, as compared with the mammalian brain. Preliminary analysis of adjacent sections stained with antisera against GABA or serotonin indicated that the histamine cells were not immunoreactive for these. The pathways and distribution of histaminergic fibers in Xenopus brain showed many similarities to mammals. The densest fiber networks were present in the medial basal forebrain, particularly in the medial amygdala and septum. A distinct cluster of fibers was concentrated around the cell bodies of nucleus accumbens. In most pallial areas, the density was moderate to low. In the primordial piriform cortex and the striatum, very few fibers were seen. In diencephalon, highest fiber densities were found in the anterior and ventral thalamus and posterior and lateral hypothalamus. In hindbrain, the density was highest in the medullary central gray, as in some mammals. The results suggest that the general pattern of the histaminergic system in vertebrate brain is conserved from amphibians to mammals.

Animals↗