Biomedical subjects

S Soinila

Publications and source records attributed to S Soinila.

At least 55 records · Page 3Linked to original sources

PubMed1995

Changes in substance P-immunoreactive innervation of human colon associated with ulcerative colitis.

The amount of colonic substance P and substance P-receptors is increased in ulcerative colitis, which may denote that substance-P is involved as a neurogenic mediator in the inflammatory process of ulcerative colitis. We studied the anatomical distribution of elevated colonic substance P in ulcerative colitis and assessed morphometrically whether the changes in substance P correlate with alterations in colonic innervation. Full-thickness specimens of colonic wall were obtained from normal human colons (N = 9) and the most and least affected regions of ulcerative colitis colons (N = 10) and immunostained for substance P. Substance P immunoreactivity index was calculated by multiplying each intensity value by the number of pixels exhibiting this intensity value. The numbers of substance P-immunoreactive nerve fibers in the lamina propria were markedly increased, and their fluorescence intensity was enhanced in ulcerative colitis. The longitudinal muscle layer contained substance P-immunoreactive nerve fibers in ulcerative colitis, but not in the controls. The substance P-immunoreactive index (= number x intensity of nerve fibers) was 3.42 +/- 1.49 in controls, 21.19 +/- 7.79 in mild ulcerative colitis regions (P < 0.05), and 29.68 +/- 9.81 in severe ulcerative colitis regions (P < 0.01). Increase in the number of substance P nerve fibers is in accordance with the hypothesis that substance P contributes to neurogenic mediation of inflammation in ulcerative colitis.

Aged↗

PubMed1995

Distribution of neurofilament proteins and peripherin in the rat pituitary gland.

The distribution of neurofilament proteins and peripherin in the pituitary gland of the rat was studied with a panel of monoclonal and polyclonal antibodies recognizing different neurofilament subunits. In the posterior lobe, a dense plexus of neurofilament- and peripherin-immunoreactive fibers was seen. In the intermediate lobe neurofilament- and peripherin-immunoreactivity was seen only in nerve fibers in the connective tissue septa, while no immunoreactivity was seen in parenchymal nerve fibers. Bilateral sympathetic ganglionectomy did not affect peripherin-immunoreactivity, indicating that the peripherin-immunoreactive fibers are of central origin. In the anterior lobe, a few solitary neurofilament- and peripherin-immunoreactive fibers were observed. Western blotting confirmed the presence of 150 kD and 200 kD neurofilament proteins in the posterior lobe. No neurofilament protein was detected in the intermediate and anterior lobes. Abundant intermediate filaments were seen with electron microscopy in the nerve fibers of the connective tissue septa in the intermediate lobe. In the parenchymal nerve fibers only microtubules were seen, indicating that the lack of neurofilament immunoreactivity is due to absence of neurofilaments.

Animals↗

PubMed1995

Release of false transmitter serotonin from the dopaminergic nerve terminals of the rat pituitary intermediate lobe.

Rat pituitary intermediate lobe contains two types of serotonin-immunoreactive nerve terminals. Most of them are dopaminergic, in which serotonin acts as a false transmitter, while the rest are true serotoninergic nerves. In the present study, release of the false transmitter serotonin from the dopaminergic nerve terminals was studied by loading the neurons in vivo with serotonin precursor L-tryptophan and MAO inhibitor pargyline, which results in accumulation of false transmitter serotonin. Subsequently pituitary neurointermediate lobe complexes were incubated in the presence of various agents. Potassium induced dramatic release of serotonin. This release was Ca(2+)-dependent, as demonstrated by an inhibition by Mg2+, and transporter-independent, since it was unaffected by GBR 12909 (a dopamine transport inhibitor). Tyramine and sodium nitroprusside, a nitric oxide donor, caused slight to remarkable release of serotonin. This release was inhibited by GBR 12909, suggesting that it was transporter-dependent. Presynaptic stimulation with apomorphine or haloperidol, dopamine receptor agonist or antagonist, respectively, or isoproterenol, agonist of the beta-adrenergic receptor, did not significantly release serotonin. Thus, it seems that presynaptic receptors per se cannot induce release of significant amounts of serotonin from the IL dopaminergic fibers. Our results suggest that false transmitter serotonin in the IL dopaminergic nerve terminals is released primarily by the classical exocytotic release mechanism, but may also be partly released by the transporter-dependent, non-exocytotic release.

Animals↗

PubMed1995

Nitric oxide synthase in the hypothalamo-pituitary pathways.

Several histochemical and physiological studies in the literature suggest that nitric oxide (NO) is involved in the posterior pituitary regulation. This study was set out to demonstrate the distribution of the pituitary projecting nitric oxide containing hypothalamic pathways. The fluorescent retrograde tracer fluorogold (FG) was injected into the pituitary gland in order to reveal the hypothalamic nuclei projecting to the pituitary gland. Nitric oxide synthase (NOS) was subsequently visualized from the same sections by NADPH-diaphorase histochemistry. More than 70% of the FG labelled neurons in the preoptic area, paraventricular, supraoptic, retrochiasmatic, anterior commissural and circular nuclei as well as in many other small neurosecretory centers in the hypothalamus contained also NADPH-diaphorase activity (NADPH-DA). In addition, some of the neurons in the periventricular nucleus as well as occasional neurons in the lateral hypothalamus projecting to the pituitary gland contained NADPH-DA. The present results give the first systematic neuroanatomical description of the hypothalamic NO synthase containing neurons projecting into the pituitary gland. They indicate that the pituitary receives a widely distributed NO innervation, which originates mostly in the magnocellular neurosecretory hypothalamo-pituitary system. In addition, the finding that some presumably non-neurosecretory pituitary-projecting neurons contain NO as well suggests that NO might be a more widely used regulator of the posterior pituitary secretion than previously expected.

Amino Acid Oxidoreductases↗

PubMed1994

NADPH-diaphorase activity and its colocalization with transmitters and neuropeptides in the postganglionic neurons of the rat superior cervical ganglion.

NADPH-diaphorase activity (NADPH-DA), a marker of neural nitric oxide synthase, was found in many postganglionic nerve cell bodies in the adult rat superior cervical ganglion (SCG) after colchicine treatment, postganglionic nerve trunk ligation or ganglion culture. NADPH-DA colocalized with immunoreactivity to tyrosine hydroxylase (TH), serotonin, vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), methionine-enkephalin and somatostatin. Almost all cells showing NADPH-DA were TH-immunoreactive, although several TH-immunoreactive cells lacked NADPH-DA. While suggesting that nitric oxide has an important role in the neuronal modulation in the synaptic transmission in the rat SCG, our results point out that nitric oxide synthesis is confined to a subpopulation of ganglion neurons. Our findings confirm the idea that the superior cervical ganglion consists of several subpopulations in which noradrenaline is colocalized with other transmitter or neuropeptide. Only about one-fourth of serotonin-immunoreactive neurons contained NADPH-DA. Similarly, the neuropeptides studied showed only partial colocalization with NADPH-DA. Our results thus suggest that nitric oxide is not associated with any particular transmitter or peptide.

Animals↗

PubMed1994

Production and characterization of a monoclonal antibody against human calcitonin gene-related peptide (CGRP) and its immunohistochemical application to salivary glands.

A monoclonal antibody (mAb), 129CD8 was raised against a C-terminal fragment (aa28-37) of alpha-human calcitonin gene-related peptide (CGRP) coupled to bovine serum albumin. The specificity of the monoclonal antibody 129CD8 was corroborated by dot immunobinding experiments, enzyme-linked immunoassay and immunostaining of tissue sections. In vitro studies showed that the mAb 129CD8 readily recognized the fragment 28-37 of alpha-human CGRP and to a slightly lesser degree whole alpha-human CGRP and the fragments containing the C-terminal part of the molecule. The mAb 129CD8 also recognized the beta-human CGRP but not the alpha-rat CGRP. The mAb 129CD8 did not react with substance P, katacalcin, calcitonin, amylin or fragments of alpha-human CGRP lacking the C-terminal part of the molecule. Immunocytochemical staining was performed on human skin, guinea-pig thyroid and salivary glands and the trigeminal ganglion, and rat thyroid gland. Our findings demonstrate, in keeping with previous studies, that in human skin, nerve fibres containing CGRP immunoreactivity are found in both epidermis and dermis. In accordance with previous investigators, the Merkel cells were immunoreactive for CGRP. In the guinea-pig and rat thyroid gland CGRP immunoreactivity was localized in the C-cells. The distribution of CGRP immunoreactivity in the guinea-pig salivary glands is different from that previously reported for rat salivary glands. In the guinea-pig trigeminal ganglion, CGRP immunoreactivity was localized mainly in small-sized neurons and fibres traversing the ganglion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Regulation of secretory granule formation in chronically hypersecretory melanotrophs in the rat pituitary.

The formation of secretory granules in chronically hypersecretory melanotrophs in the rat pituitary was studied. Hypersecretion was induced by treatment with the dopamine antagonist haloperidol (1.5 mg/kg daily for 7 days), which releases the normal neural dopaminergic inhibition of secretion from the melanotroph. Morphometric analysis showed a 100% increase in the volume fraction of granular endoplasmic reticulum after haloperidol treatment, while the volume fractions of electron-dense granules, electron-lucent granules and the Golgi apparatus were unaltered. The mean diameter of the mature secretory granules was increased by 10%, indicating a 30% increase in mean granule volume. A similar increase in diameter was observed in condensing granules within the Golgi area. With earlier results on the effect of chronic inhibition the study shows that a main adaptive response of the melanotroph to altered secretory conditions is a change in the volume of the secretory granules, regulated by a mechanism that operates at an early stage of granule formation.

Animals↗

PubMed1994

Pharmacological characterization of serotonin synthesis and uptake suggest a false transmitter role for serotonin in the pituitary intermediate lobe.

A subpopulation of nerve fibers in the rat pituitary intermediate lobe (IL) have been shown to exhibit colocalization of serotonin (5-HT-IR) and tyrosine hydroxylase immunoreactivities and they are sensitive to neurotoxins specific to catecholamine neurons. This study was set out to examine the uptake and synthesis mechanisms of serotonin in these fibers. We developed an in vitro technique in which the neurointermediate lobe explants were incubated (14 and 48 h) in the presence of various drugs and serotonin was subsequently visualized by immunohistochemistry. Control incubation in the presence of serotonin (10(-6) M) resulted in a rich plexus of 5-HT-IR fibers in both posterior and intermediate lobes. Fluoxetine and citalopram (10(-6) M and 10(-5) M), inhibitors of 5-HT transporter, did not affect 5-HT-IR in the IL fibers, unless they were used in concentrations high enough (10(-4) M and 10(-3) M) to block unspecifically a number of monoamine transporters. The same applied for desipramine (10(-5)-10(-7) M), an inhibitor of the noradrenaline transporter. However, cocaine (10(-5)-10(-6) M) blocked serotonin uptake into these terminals, suggesting that serotonin uptake occurs through a dopamine transporter. Incubation of the IL in presence of L-tryptophan (10(-4) M) did not result in 5-HT-IR in the IL fibers showing colocalization of 5-HT-IR and tyrosine hydroxylase, which suggests that these fibers do not synthesize serotonin. The present results suggest that serotonin is taken up into the IL terminals by a dopamine transporter and is not synthesized in them, at least in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Neurotrophins and their receptors in the rat pituitary gland: regulation of BDNF and trkB mRNA levels by adrenal hormones.

We studied the expression of messenger ribonucleic acids (mRNAs) for neurotrophins and neurotrophin receptors in the rat pituitary gland and examined the influence of adrenal hormones on their mRNA levels, using in situ hybridization and Northern blot analysis. The only neurotrophin present at detectable levels in the pituitary was brain-derived neurotrophic factor (BDNF), which was observed in the anterior and intermediate lobes. Several transcripts of the putative receptor for BDNF, trkB, were present in the anterior and posterior lobes of the pituitary. A low amount of trkC mRNA was found in both the anterior and the intermediate lobe. Dexamethasone treatment decreased both BDNF and trkB mRNA levels in the anterior lobe of the pituitary. Adrenalectomy had no effect on trkB expression, but it decreased BDNF mRNA levels in comparison to the control animals. This effect could not be reversed by dexamethasone substitution, suggesting that BDNF, mRNA levels may be regulated not only by glucocorticoids but also by other adrenal hormones. These results demonstrate that BDNF, trkB and trkC are expressed in the pituitary gland and that glucocorticoids and possibly other adrenal hormones may modulate pituitary functions by regulating the expression of neurotrophic factors and their receptors. Whether BDNF acts as a secreted hormone, a trophic factor, or has autocrine/paracrine functions within the pituitary through its receptor, trkB, remains to be studied.

Animals↗

PubMed1993

Endocytotic pathways in the melanotroph of the rat pituitary.

The internalization of the extracellular markers horseradish peroxidase (HRP) and cationized ferritin (CF) by the melanotrophs of the intermediate lobe of the rat pituitary was studied during short-time incubation of mechanically dissociated cells or in cell culture after 5 days. After a 30 min exposure, the tracers were found in electron-lucent granules or vacuoles of approximately the same size as the secretory granules, situated 200-500 nm from the cell membrane. In the cultured cells, which showed a higher rate of tracer uptake, internalization was followed for 1, 2 and 5 min after labelling and during 2 h of exposure. Initially, the label was seen only in coated pits and coated vesicles at the cell membrane. Larger vacuoles were first seen after 2-5 min of incubation. After 2 h of exposure the labelling pattern was distinctly different for the two tracers. CF was found in larger vacuoles of varying morphology, in dilatations at the base of cilia, within Golgi saccules and at the edge of the electron-dense core of forming secretory granules. HRP was found in an extensive array of tubulovesicular structures extending throughout the cytoplasm. The Golgi complex and forming granules were, however, not labelled with HRP. The study identifies part of the electron-lucent granules or vacuoles in the melanotroph as endosomes, and shows that the melanotrophs sort CF and HRP via diverting pathways after internalization, suggesting that granule membrane, and possibly its functional components, can be recycled in these cells.

Animals↗

PubMed1993

Comparison of immunohistochemical localization of [Met5] enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide and tyrosine hydroxylase in the major pelvic ganglion of the rat.

The major pelvic ganglion is an autonomic ganglion containing both sympathetic and parasympathetic postganglionic neuronal cell bodies. The existence of the proenkephalin A-derived peptide [Met5]enkephalin-Arg6-Gly7-Leu8 immunoreactivity in the rat major pelvic ganglion has been described quite recently. The aim of this study was to compare the relations of [Met5]enkephalin-Arg6-Gly7-Leu8-containing postganglionic neurons and nerve fibers to noradrenergic (tyrosine hydroxylase-immunoreactive) and non-noradrenergic (putative cholinergic) neurons of the rat major pelvic ganglion. Immunohistochemical double staining and elution-restaining techniques were used to investigate the distribution of [Met5]enkephalin-Arg6-Gly7-Leu8 in correlation with tyrosine hydroxylase and vasoactive intestinal polypeptide. The major pelvic ganglion contained neurons immunoreactive either for tyrosine hydroxylase or vasoactive intestinal polypeptide. Many principal neurons, however, were immunoreactive for tyrosine hydroxylase nor vasoactive intestinal polypeptide. [Met5]Enkephalin-Arg6-Gly7-Leu8-immunoreactive principal neurons formed a minor subpopulation in the ganglion and were not immunoreactive for tyrosine hydroxylase. The majority of [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive principal cells were non-immunoreactive for vasoactive intestinal polypeptide, but a few of them also contained vasoactive intestinal polypeptide. In contrast to the large [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive principal neurons, which formed a population of non-noradrenergic (putative cholinergic) cells, the small [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive cell exhibited intense tyrosine hydroxylase immunofluorescence and represented a subpopulation of small, intensely fluorescent cells. [Met5]Enkephalin-Arg6-Gly7-Leu8-immunoreactive pericellular fiber plexuses were found around tyrosine hydroxylase- and vasoactive intestinal polypeptide-immunoreactive principal neurons and in association with small intensity fluorescent cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

A new monoclonal antibody against the GABA-protein conjugate shows immunoreactivity in sensory neurons of the rat.

A monoclonal antibody, 115AD5, was raised against GABA coupled to bovine serum albumin. The monoclonal antibody 115AD5 also reacted with other GABA-protein conjugates. The specificity of the monoclonal antibody was corroborated by enzyme-linked immunoassay, dot-immunobinding experiments and immunostaining of rat cerebellum sections. The monoclonal antibody 115AD5 could successfully be applied on Vibratome and cryostat sections using either indirect immunofluorescence or peroxidase techniques. In rat cerebellar cortex the monoclonal antibody 115AD5 gave an intense immunoreaction in stellate cells, in Golgi neurons, and in basket cells and their processes around Purkinje cell bodies. Purkinje cell dendrites showed GABA immunoreactivity while the cell bodies were non-reactive or only weakly reactive. There was labelling in some nuclei of Purkinje cells. GABA immunoreactivity was also found in dot-like structures in the granular layer. A large population of sensory neurons in rat thoracic and lumbar spinal dorsal root ganglia presented an intense immunoreactivity for the monoclonal antibody 115AD5. Nerve bundles immunoreactive for GABA were also seen in these ganglia. In the trigeminal ganglion, a major population of sensory neurons and some of their processes presented immunoreactivity for GABA. In the sensory nodose ganglion of the vagus nerve, many neuronal cell bodies and some fibres were immunoreactive for GABA. Ligation of the vagus nerve caudal to the ganglion resulted in an increased GABA immunoreactivity in neuronal somata of the ganglion, as well as in nerve fibres on the ganglionic side of the ligature. The present results suggest that in the rat, a population of sensory neurons in thoracic and lumbar spinal dorsal root ganglia, as well as in the trigeminal and nodose ganglia contain GABA. The presence of GABA immunoreactivity in these neurons raises the possibility of a neurotransmitter or modulator role.

Animals↗

PubMed1992

Immunohistochemistry of enkephalins: model studies on hapten-carrier conjugates and fixation methods.

For immunohistochemical demonstration of the enkephalin octapeptide Met5-enkephalin-Arg6-Gly7-Leu8, the peptide was conjugated with a carrier protein using either glutaraldehyde or 1-ethyl-3 (3-dimethylaminopropyl)-carbodiimide as coupling agent. Antisera were raised in rabbits and their specificity was studied using the immunoblotting technique. The results suggest that glutaraldehyde selectively couples the amino terminus of the peptide to the carrier protein, while carbodiimide coupling produces a mixture of specificities. Accordingly, antiserum raised against the glutaraldehyde-induced conjugate specifically recognized the peptide carboxyl terminus and allowed immunohistochemical distinction of the octapeptide from other closely related opioid peptides, such as Leu5- and Met5-enkephalin, Met5-enkephalin-Arg6-Phe7, and Phe1-Met2-Arg3-Phe4-NH2. In contrast, antiserum raised against the carbodiimide-induced octapeptide conjugate showed a mixture of specificities. Addition of glutaraldehyde to the fixative enhanced octapeptide immunoreactivity in several tissues and revealed a previously unknown nerve system in the pituitary gland. These results support the idea that optimal immunohistochemical demonstration of small molecules, which requires conjugation to a carrier protein, is obtained when the coupling agent is included in the fixative so as to induce the actual coupling reaction during fixation.

Amino Acid Sequence↗

PubMed1991

Distribution of Met5-enkephalin-Arg6-Gly7-Leu8-immunoreactivity in the rat and mouse pituitary gland.

The distribution of the octapeptide Met5-enkephalin-Arg6-Gly7-Leu8 (MEAGL), a proenkephalin A-derived opioid peptide, in the rat and mouse pituitary gland was studied using the indirect immunofluorescence technique and immunoelectron microscopy. The anterior lobe contained a few MEAGL-immunoreactive cells but no nerve fibers. A previously unknown enkephalin-immunoreactive nerve fiber system was revealed in the intermediate lobe. These fibers originated in a dense MEAGL-immunoreactive plexus located along the border between the intermediate and posterior lobes and were distributed throughout the lobe. In the posterior lobe, MEAGL immunoreactivity was found in a very dense network of varicose fibers that was evenly distributed over the entire lobe. These results provide a morphological correlate for previous chemical studies and together with them suggest that MEAGL-immunoreactive innervation regulates endocrine functions of the intermediate and posterior lobes directly at the pituitary level.

Animals↗

PubMed1991

Met5-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerve fibers in the major salivary glands of the rat: evidence for both sympathetic and parasympathetic origin.

The localization of the proenkephalin A-derived octapeptide, Met5-enkephalin-Arg6-Gly7-Leu8 (MEAGL), was studied in the major salivary glands of Sprague-Dawley and Wistar rats with the indirect immunofluorescence method. MEAGL-immunoreactive nerve fibers were found around the acini, along intra- and interlobular salivary ducts and in close contact with blood vessels. In the parotid and submandibular glands tyrosine hydroxylase (TH) immunoreactivity was observed in nerve fibers around the acini, in association with intra- and interlobular salivary ducts and around blood vessels, while in the sublingual gland TH-immunoreactive nerve fibers were only seen around blood vessels. Parasympathetic neurons in submandibular ganglia contained MEAGL immunoreactivity. Moderate TH immunoreactivity was seen in some neurons of the submandibular ganglia. A subpopulation of sympathetic principal neurons in the superior cervical ganglion were immunoreactive for both MEAGL and TH. In the trigeminal ganglion, no MEAGL-immunoreactive sensory neurons or nerve fibers were observed. Superior cervical ganglionectomies resulted in a complete disappearance of TH-immunoreactive nerve fibers, while MEAGL-immunoreactive nerve fibers were still present in the glands. The presence of MEAGL immunoreactivity in neurons of both sympathetic superior cervical ganglia and parasympathetic submandibular ganglia and the results of superior cervical ganglionectomies suggest, that MEAGL-immunoreactive nerve fibers in the major salivary glands of the rat have both sympathetic and parasympathetic origin.

Animals↗

PubMed1991

Immunohistochemical localization of [Met5]enkephalin and [Met5]enkephalin-Arg6-Gly7-Leu8 in sympathetic and parasympathetic neurons and nerve fibers projecting to the rat submandibular gland.

The localization of [Met5]enkephalin, [Met5]enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide and tyrosine hydroxylase immunoreactivities was studied in the submandibular gland of adult Sprague-Dawley and Wistar rats using the indirect immunofluorescence technique. Immunoreactivities for [Met5]enkephalin and [Met5]enkephalin-Arg6-Gly7-Leu8, a proenkephalin A-derived octapeptide, showed identical distributions. A large number of enkephalin-immunoreactive nerve fibers were detected around secretory acini, along intercalated ducts, convoluted granular tubules, intra- and interlobular ducts, as well as in close contact with blood vessels. The submandibular ganglia contained several enkephalin-immunoreactive neurons and nerve fibers. In the superior cervical ganglion numerous enkephalin-immunoreactive neurons and nerve fibers were also detected. Immunohistochemical co-localization studies indicated that [Met5]enkephalin and [Met5]enkephalin-Arg6-Gly7-Leu8 immunoreactivities co-exist with vasoactive intestinal polypeptide in a subpopulation of neurons of the rat submandibular ganglia, in nerve trunks along the salivary ducts of the gland, and in nerve fibers around the acini. Uni- or bilateral superior cervical ganglionectomies for 1-4 weeks resulted in a complete disappearance of tyrosine hydroxylase immunoreactivity in the glandular parenchyma, while moderate tyrosine hydroxylase immunoreactivity was seen in some neurons of the submandibular ganglia. Abundant [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive nerve fibers were still seen around the acini and blood vessels, as well as close to salivary ducts. These operations did not affect the [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive neurons in the submandibular ganglia. Many principal neurons in the superior cervical ganglion contained both [Met5]enkephalin-Arg6-Gly7-Leu8 and tyrosine hydroxylase immunoreactivity. Nerve ligation experiments indicated that [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive sympathetic fibers project along the external carotid nerve. Accordingly, nerve fibers were found around the acini and blood vessels as well as in nerve trunks along the salivary ducts of the submandibular gland, showing co-localization of [Met5]enkephalin-Arg6-Gly7-Leu8 and tyrosine hydroxylase. Taken together, these observations suggest that the nerve fibers of the rat submandibular gland containing proenkephalin A-derived peptides are of both sympathetic and parasympathetic origin.

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

Phenylethanolamine N-methyltransferase-(PNMT)-like immunoreactivity in the rat parathyroid gland.

A phenylethanolamine N-methyltransferase-(PNMT)-immunoreactivity, present without the other catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH), has been previously detected in the central nervous system and in endocrine cells of the islets of Langerhans and the pituitary intermediate lobe of the rat. In the present study a similar PNMT-like immunoreactivity is demonstrated in the rat parathyroid gland. The immunoreactivity was distinctly localized to the cell periphery, and present in all glandular cells. The thyroid gland was negative. In the parathyroid TH- and DBH-immunoreactivity was seen only in vascular nerve fibers; no glandular cells were stained. The functional significance of the PNMT-like immunoreactivity is not known. The absence of TH- and DBH-immunoreactivity and the low level of adrenaline detected in the parathyroid, and the peripheral localization of the immunoreactivity may indicate an alternative enzyme function or the detection of an immunologically related protein common to pancreatic, pituitary and parathyroid endocrine cells.

Animals↗