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Biomedical subjects

C Sternini

Publications and source records attributed to C Sternini.

At least 91 records · Page 5Linked to original sources
PubMed1989

Expression and cellular localization of substance P/neurokinin A and neurokinin B mRNAs in the rat retina.

The mammalian tachykinin peptides, substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) are encoded by distinct mRNAs derived from separate preprotachykinin (PPT) genes. The SP/NKA-encoding PPT gene generates three mRNAs by alternative RNA processing: alpha-PPT mRNA, which encodes SP only, and beta- and gamma-PPT mRNAs, which encode both SP and NKA. The NKB-encoding PPT gene generates mRNAs that produce NKB. The distribution and cellular localization of SP, NKA and NKB mRNAs in the rat retina were studied by RNA blot and in situ hybridization techniques. Blot hybridization analysis of retinal RNA extracts with [32P]-labeled RNA probes complementary to SP/NKA and NKB mRNAs demonstrated single bands of hybridization at 1300 and 900 bases, respectively. Solution hybridization-nuclease protection experiments showed multiple SP/NKA-encoding transcripts with relative levels of gamma-PPT mRNA greater than beta-PPT mRNA much greater than alpha-PPT mRNA. In situ hybridization histochemistry with [35S]-labeled antisense RNAs demonstrated that SP/NKA-encoding transcripts are expressed in small-to-medium somata located in the proximal inner nuclear, inner plexiform, and ganglion cell layers, whereas NKB-encoding transcripts are expressed in small-to-medium somata located only in the ganglion cell layer. In this layer, cells containing NKB mRNAs are more numerous than those containing SP/NKA mRNAs. Only background labeling was observed in sections incubated with sense RNA probes, pretreated with RNase A prior to hybridization or incubated in hybridization buffer without the labeled probe. Immunohistochemical studies with a monoclonal antibody directed to the conserved COOH-terminal sequence of the tachykinin peptides revealed tachykinin-like immunoreactive somata with similar size and distribution to those containing SP/NKA- and NKB-encoding transcripts. These results indicate that both SP/NKA and NKB mRNAs are present in the rat retina and that the PPT genes are differentially expressed in specific cell populations. The size and distribution of these cells suggest that they are amacrine and displaced amacrine cells, however, the possibility that tachykinins are present also in ganglion cells in the rat retina cannot be ruled out.

Amino Acid Sequence↗
PubMed1989

Calcitonin gene-related peptide (CGRP)-positive neurons and fibers in the cat periaqueductal grey matter.

The morphology and topographical distribution of neurons and terminals containing calcitonin gene-related peptide (CGRP) immunoreactivity in the cat periaqueductal grey (PAG) were studied using a rabbit antiserum raised against the C-terminal region of rat alpha-CGRP. In normal cats, numerous fibers, but rarely immunoreactive neurons, were observed in the PAG. CGRP-containing fibers showed bouton-like swellings along their length and expanded in terminal clusters of boutons. In many cases, CGRP-positive fibers were also observed in close association with small blood vessels. Immunoreactive fibers were particularly numerous at caudal PAG levels, mostly in its ventrolateral portion. In colchicine-treated cats, the pattern of CGRP-containing fibers was basically unchanged, despite a reduction of both the number of fibers and the intensity of fiber staining; in addition, numerous CGRP-positive neurons were found, mostly in the ventrolateral portion of the caudal PAG. These neurons were fusiform, spheroidal, and triangular in shape. The selective distribution of CGRP-positive elements in the PAG suggests a functional specialization of these neurons in the activation of pain-modulating mechanisms.

Animals↗
PubMed1988

Calcitonin gene-related peptide (CGRP) in the rat central nervous system: patterns of immunoreactivity and receptor binding sites.

The distribution of immunoreactive (IR) axons and neurons in the rat central nervous system (CNS) has been studied with an antiserum directed against the C-terminal sequence of rat a-calcitonin gene-related peptide (CGRP) and a durable peroxidase reaction product for detailed analysis in relation to normal cytoarchitecture. These materials were studied and illustrated in the three principal axes in relation to cell-stained adjacent sections in normal as well as colchicine- and capsaicin-treated animals, although no fundamental differences in pattern were evident in neurotoxin-treated rats. The patterns of CGRP-IR were then compared with autoradiograms of specific, high affinity receptor binding sites for 125I-human a-CGRP. CGRP-IR labeling in motor systems includes the vast majority of motoneurons, enabling facile identification of isolated 'accessory' populations. Preganglionic parasympathetic nuclei revealed only labeling of a small proportion of neurons. By contrast, the sensory systems revealed a diversity of labeling patterns precluding simple generalizations. Peripheral input ranges from extensive labeling of thin somatic afferents, feeble to moderate gustatory and olfactory afferents to a total absence of auditory afferents, yet IR axons and neurons can be found in selective distribution within each of these sensory systems. Patterns of IR in various integrative centers, e.g. cerebellum, basal ganglia and hypothalamus, reveal selectivity that fails to conform to conventional descriptions of functional systems. Some regions display unexpected patterns, e.g. vertical stripes in cerebellar cortex. CGRP receptor binding sites (RB) are found in many of the sites where IR axons terminate and in some cases, e.g. motor neurons, which express intraneuronal IR. The main sensory systems reveal a variety of RB patterns, only a few of which can be related to sites of IR axon terminals. Many apparent 'mismatches' between IR and RB are illustrated and discussed in the context of functional peptide expression or in quasi-hormonal terms. It is suggested that the principle of CGRP-IR axon distribution in peripheral tissues, where synapses are lacking, might also apply to the CNS and that neither the locus of IR-axon terminals nor RB sites need indicate transmitter action for impulse information transfer. CGRP is a widely distributed neuromodulator probably subserving a role in both synaptic and metabolic regulation, depending on the specific requirements of the diverse distribution of its receptors.

Animals↗
PubMed1988

Distribution of calcitonin gene-related peptide immunoreactivity in relation to the rat central somatosensory projection.

The distribution of the neuropeptide calcitonin gene-related peptide (CGRP) was studied in relation to the known subcortical somatosensory pathways and contiguous systems in the central nervous system (CNS) of rats by using peroxidase histochemical methods in order to relate zones of immunoreactivity (IR) to cytoarchitecture. CGRP is the most ubiquitous peptide found to date in sensory ganglion cells: principally small and medium-size neurons emitting thin axons inferred to be largely nociceptive in function on the basis of the peripheral distribution of their terminals. Its apparent absence in sympathetic axons provides an especially useful sensory marker. The distribution of CGRP-IR axons displays remarkable selectivity at each level of the CNS. The trigeminal root distributes axons primarily to the pericornual layers (laminae I and II) of spinal V nucleus caudalis and to subnucleus oralis, evading the subnucleus interpolaris and contributing only few axons to principal V. Although there are only a few CGRP-IR somata at each level, heavily labeled axon trajectories can be traced to the nuclei of the solitary tract, the parabrachial nuclei, several sectors of the caudal medial thalamus, and the central nucleus of the amygdala. A sector of labeled neuron somata lies contiguous to each of these axon terminal zones, the largest of which is a thalamic nucleus containing cells of distinctive dendritic architecture extending from the periaqueductal gray across the posterior group nuclei to the peripeduncular nucleus, forming a linear array at the mesodiencephalic junction. The relation of CGRP-IR axonal distribution to spinothalamic, visceral, and gustatory systems is discussed in the context of a specialized "chemosensory" component of the thin-fiber somatosensory system.

Animals↗
PubMed1988

Neurons containing calcitonin gene-related peptide in the parabrachial nucleus project to the central nucleus of the amygdala.

The source, distribution, and morphology of axons displaying calcitonin gene-related peptide (CGRP) immunoreactivity in the central amygdaloid nucleus of the adult rat were investigated with immunohistochemical techniques, both alone and in combination with retrograde transport of fluorescent tracers. An extremely dense plexus of CGRP-immunoreactive axons is differentially concentrated within the lateral capsular and lateral central subdivisions of the central nucleus, and much lighter concentrations of labeled fibers are present in the rostral part of the medial subdivision. No immunoreactive neurons were observed in the central nucleus in any of the experimental animals. The immunoreactive axons characteristically form prominent pericellular terminal arborizations surrounding unlabeled neurons. The number of cells receiving this dense input increases at caudal levels of the central nucleus. Retrograde label of central nucleus neurons by dye transport from injections into the pontine parabrachial nucleus and the nucleus of the tractus solitarius combined with CGRP immunohistochemistry established that many neurons in the central nucleus which receive dense pericellular innervation from CGRP-immunoreactive axons are projecting caudally to the parabrachial nucleus or, to a lesser extent, to the nucleus tractus solitarii. Central amygdaloid injections of rhodamine-labeled microspheres or fluorogold followed by immunohistochemical localization of cellular CGRP immunoreactivity revealed that the central amygdaloid CGRP fiber plexus originates bilaterally from the parabrachial nucleus. These multipolar CGRP-containing neurons are preferentially concentrated in the external medial and external lateral subnuclei, in the ventral aspect of the parabrachial nucleus. These results relating central amygdaloid CGRP to ascending and descending brainstem pathways, taken together with the extreme density of the fiber plexus, strongly suggest the relevance of the CGRP input to central nucleus function in cardiovascular and other autonomic regulation.

Amygdala↗
PubMed1988

Calcitonin gene-related peptide immunoreactivity in the biliary pathway and liver of the guinea-pig: distribution and colocalization with substance P.

Calcitonin gene-related peptide immunoreactivity was localized immunohistochemically in nerve fibers innervating the biliary pathway and liver of the guinea-pig. Immunoreactive fibers are present in all layers of the gallbladder and biliary tract and are particularly numerous around blood vessels. In the liver, immunoreactive processes are usually restricted to the interlobular space and porta hepatis, and only a few, very thin, beaded processes were observed in the hepatic parenchyma. A rich innervation is also associated with the vena portae. Positive ganglion cell bodies were not visualized within the ganglionated plexus of the biliary system, whereas they were found in the myenteric and submucosal plexus in the cranial portion of the duodenum corresponding to the sphincter of Oddi. The vast majority, if not all, of calcitonin gene-related peptide-immunoreactive fibers contain substance P immunoreactivity; however, there are some substance P-containing fibers lacking calcitonin gene-related peptide immunoreactivity. The lack of co-occurrence of calcitonin gene-related peptide and substance P immunoreactivities in intrinsic ganglion cells suggests that these two peptides are coexpressed in the extrinsic component of the innervation of the hepatobiliary system.

Animals↗
PubMed1988

Structural and chemical organization of the myenteric plexus.

The most striking characteristics of the myenteric plexus are the heterogeneity of its neuronal populations and the complexity of its organization. Myenteric neurons greatly differ in their morphological characteristics, projection patterns, and topographical arrangement within the ganglia. The discovery of histochemically distinct types of neurons together with the development of nerve-tracing techniques and specific lesions have allowed a better understanding of the relationships of enteric neurons to specific target tissues. Consequently, these techniques have contributed significantly to our knowledge of the highly ordered organization of the ENS, which represents the anatomical substrate for the neural coordination and integration of the complex functions it subserves. The existence of different types of neurons that probably use different substances as transmitters may reflect on the existence of defined functional roles for each type of neurons. To date, only ACh, NE, and probably 5-HT seem to satisfy all the criteria necessary for establishing a neurotransmitter, although there is increasing evidence that some of the other substances, such as GABA, SP, and VIP, are enteric transmitters or modulators. The functional roles of the different types of neurons in the neural circuitry that regulates gastrointestinal functions remain to be elucidated.

Animals↗
PubMed1987

Distribution and characterization of calcitonin gene-related peptide immunoreactivity in the digestive system of normal and capsaicin-treated rats.

The distribution and characterization of calcitonin gene-related peptide immunoreactivity in the digestive system of normal, capsaicin-treated, and littermate control rats were studied by radioimmunoassay, chromatography, and immunohistochemistry. The highest concentrations of calcitonin gene-related peptide immunoreactivity were found in the stomach (45 +/- 2.8 pmol/g wet wt, nonsecretory region; 38.7 +/- 4.4 pmol/g wet wt, secretory region) and rectum (30.9 +/- 1.6 pmol/g wet wt). Significant amounts of peptide were also found in the other regions of the gut and in the pancreas. Neonatal treatment with capsaicin, which causes a permanent degeneration of most of the small-diameter sensory neurons, reduced calcitonin gene-related peptide content by greater than 95% in the esophagus and stomach, by 60% in the pancreas, and by less than 50% in the intestine, when compared with littermate controls. Separation of extracts from the gut, pancreas, and brain by chromatography gave major peaks corresponding to the predicted rat calcitonin gene-related peptide and small unidentified peaks, which presumably arise from metabolism of the peptide. Immunohistochemical studies demonstrated that in the esophagus and stomach, calcitonin gene-related peptide immunoreactivity is restricted to nerve fibers, whereas in the intestine it is localized in both nerve fibers and enteric ganglion cells. In capsaicin-treated rats there was a virtually complete elimination of calcitonin gene-related peptide immunoreactive fibers innervating the esophagus and stomach, whereas in the small and large intestine there was a dramatic reduction and often a complete elimination of those associated with blood vessels and a slighter reduction of the nonvascular immunoreactive fibers. The results of this study indicate that calcitonin gene-related peptide immunoreactive nerve fibers innervating the rat digestive system originate from both intrinsic (enteric) and extrinsic (presumably sensory) sources and that both the intrinsic and extrinsic components appear to contain a substance that corresponds to the predicted calcitonin gene-related peptide.

Animals↗
PubMed1986

Immunocytochemical identification of islet cells and nerve fibers containing calcitonin gene-related peptide-like immunoreactivity in the rat pancreas.

Calcitonin gene-related peptide-like immunoreactivity has been localized in endocrinelike or paracrinelike cells and nerve fibers of the rat pancreas. Immunoreactive cells with short and thick, elongated processes were mainly distributed at the periphery of the islets of Langerhans and occasionally disseminated among the acini. Positive varicose fibers were observed in both the endocrine and exocrine parenchyma as well as around blood vessels. Treatment with the small-diameter sensory fiber neurotoxin capsaicin resulted in virtually complete elimination of calcitonin gene-related peptide immunoreactive fibers innervating the parenchyma and blood vessels, suggesting an extrinsic, sensory origin of these fibers. The sympathetic neurotoxin 6-hydroxydopamine did not affect the immunoreactive staining. The results of this study support the possibility that a distinct cell population within the endocrine pancreas of the rat contains calcitonin gene-related peptide, and that this peptide plays both an endocrine/paracrine role, as well as a modulator role in the regulation of pancreatic function.

Animals↗
PubMed1985

Localization of calcitonin gene-related peptide-like immunoreactivity in neurons of the rat gastrointestinal tract.

Calcitonin gene-related peptide (CGRP)-like immunoreactivity was localized in neuronal processes and somata of the rat gastrointestinal tract. Varicose processes were observed in the myenteric and submucosal plexuses, smooth muscles, submucosa, mucosa and around blood vessels. Immunoreactive somata were visualized in the myenteric and submucosal ganglia of the intestine in colchicine-treated rats. These observations, together with previous neuroanatomical and pharmacological studies, suggest that CGRP may be involved in regulatory functions of the gastrointestinal tract.

Animals↗
PubMed1985

Distribution and colocalization of neuropeptide Y- and tyrosine hydroxylase-like immunoreactivity in the guinea-pig heart.

The localization and distribution of neuropeptide Y-like immunoreactivity in the guinea-pig heart were studied by use of immunohistochemical methods. A widespread distribution of immunoreactive processes was observed in all regions of the heart. They occur either singly or together with several other immunoreactive processes and are most often aligned parallel to the myocardial bundles. A dense network of processes is present in the region of both the sinuatrial and atrioventricular nodes and single fibers are occasionally observed to be closely associated with nodal ganglion cells. Positive cell bodies were not seen within the heart. All small, medium and large coronary vessels are surrounded by a dense network of immunoreactive processes. A rich innervation at the media-adventitia junction of the aorta, pulmonary trunk, superior and inferior vena cava was also observed. Comparison of adjacent sections stained with antisera directed to avian pancreatic polypeptide, carboxyl-terminal hexapeptide of pancreatic polypeptide or neuropeptide Y demonstrated a very similar immunoreactive pattern, suggesting that these antisera are reacting with the same or a closely related substance. Likewise, the same immunoreactive patterns were observed in adjacent sections incubated in antiserum to neuropeptide Y or tyrosine hydroxylase, and analysis of elution-restained sections demonstrated that the same processes contain both neuropeptide Y- and tyrosine hydroxylase-like immunoreactivity. Neuropeptide Y- and tyrosine hydroxylase-like immunoreactivity was reduced by the same magnitude after treatment with the sympathetic neurotoxin 6-hydroxydopamine, but it was not affected by the primary sensory neurotoxin capsaicin. Furthermore, the pattern of neuropeptide Y- and tyrosine hydroxylase-like immunoreactivity did not match the staining patterns observed with antisera to vasoactive intestinal polypeptide or substance P or with the acetylcholinesterase staining pattern. In conclusion, neuropeptide Y-like immunoreactivity in the heart and great vessels coexists with that for catecholamines and is likely to originate from sympathetic ganglia.

Animals↗
PubMed1984

Serum immunoreactive trypsin response to secretin injection in patients with chronic pancreatitis.

Serum immunoreactive trypsin response to secretin injection (75 clinical units iv over a 2-min period) was studied in patients with chronic pancreatitis and in control subjects. Secretin stimulation caused a slight but significant increase of basal serum immunoreactive trypsin concentration in normal subjects and a marked increase in chronic pancreatitis patients with mild to moderate insufficiency. In patients with severe insufficiency and steatorrhea it had very little effect. The integrated immunoreactive trypsin response to secretin injection in patients with mild to moderate insufficiency was significantly higher compared to controls and to patients with severe insufficiency. In the latter patients it was significantly lower than in controls. A markedly elevated response of serum immunoreactive trypsin to secretin administration seems to differentiate chronic pancreatitis patients with mild to moderate insufficiency from those with severe insufficiency and from controls.

Adult↗
PubMed1984

Effect of secretin stimulation upon serum immunoreactive trypsin in patients with carcinoma of the pancreas.

The response of serum immunoreactive trypsin (IRT) to the intravenous injection of secretin (75 clinical units) was evaluated in 14 patients with carcinoma of the pancreas and in 20 healthy control patients. A striking increase of serum IRT concentration after secretin, which was much more marked than in those in the control group, was found in patients with localized carcinoma of the pancreas, whereas no increase was observed in those with more diffuse carcinoma.

Adult↗
PubMed1983

Effect of bombesin on serum immunoreactive trypsin in healthy subjects and in patients with chronic pancreatitis.

We studied the effect of bombesin (9 ng/kg X min for 30 min by intravenous infusion) on serum immunoreactive trypsin in healthy subjects and in chronic pancreatitis patients. Bombesin administration caused a marked and significant increase of serum immunoreactive trypsin concentration in healthy subjects. The increase occurred in the first 15 min after the beginning of bombesin infusion and persisted for the duration of the study (2 h). In patients with chronic pancreatitis, the increase was much less pronounced. In these patients, the integrated immunoreactive trypsin response to bombesin was significantly correlated with bicarbonate, lipase, and chymotrypsin outputs into the duodenum. The response of serum immunoreactive trypsin to bombesin stimulation seems to vary according to the degree of pancreatic exocrine dysfunction and to reflect the functional capacity of acinar cell mass.

Adult↗
PubMed1981

Secretin-stimulated trypsin-like immunoreactivity in alcoholics.

Serum trypsin-like immunoreactivity (TLI) was studied in alcoholics without evidence of pancreatic disease and in controls. Basal values were 29 +/- 4.6 microgram/l (mean +/- S.E.M) in alcoholics and 23 +/- 4.4 microgram/l in controls (p not significant). The injection of secretin was followed by a significant increase of serum TLI in both groups; the integrated trypsin output (ITO) in the first hour after secretin administration was 947 +/- 403 (mean +/- S.E.M.) in alcoholics and 76 +/- 15 in controls (p less than 0.05). In 9 (75%) of the alcoholics tested, ITO was higher than the highest ITO of controls. The increase of serum TLI after injection of secretin is probably due to secretion and/or regurgitation of trypsinogen into the bloodstream when the pancreas is stimulated with intravenous secretin. In the light of experimental studies on chronic ethanol intoxication in animals, the increased ITO observed in alcoholics may suggest obstruction to pancreatic secretory flow in spite of the absence of any clinical sign of pancreatic disease.

Adult↗
PubMed1980

Basal and stimulated serum immunoreactive trypsin in normal subjects.

Fasting serum immunoreactive trypsin (IRT) concentrations were measured in 35 healthy subjects. In 10 of them serum IRT levels were also evaluated after administration of secretin (GIH, 75 CU i.v. over 2 minutes); in 7 after a Lundh meal; in 12 after a standard protein meal (Liebig meat extract, 15 g in 150 ml of water) and in 13 after a glucose (1 g/Kg) oral load. Serum IRT was measured by radioimmunoassay (Trypsik kit, CIS, Sorin-Biomedica, Saluggia, Vercelli, Italy). Fasting serum IRT was 25.8 +/- 9 ng/ml (mean +/- SD). No correlation was found between age and serum IRT levels, nor were any statistical differrences observed in IRT concentration between the two sexes. A standard protein meal, Lundh meal or oral load of glucose did not provoke a significant increase in serum IRT levels. Only rapid i.v. injection of secretin was able to induce a significant rise of IRT over basal levels in healthy subjects. This behaviour is probably due more to an engorgement of the pancreatic ductal system with regurgitation of trypsinogen into the blood steam rather than to a direct effect of secretin on the synthesis and secretion of trypsin or to intestinal reabsorption of this enzyme.

Adolescent↗
PubMed1980

Serum immunoreactive trypsin after secretin stimulation in chronic pancreatitis.

Serum immunoreactive trypsin (IRT) response to secretin injection was studied in 13 patients with chronic pancreatitis with different degrees of exocrine dysfunction and in 10 control subjects. The maximal increase of serum IRT from basal values and the integrated trypsin output (ITO) after secretin administration were significantly correlated with the output of chymotrypsin into the duodenum during caerulein-secretin infusion (p < 0.01), but not with the output of lipase nor of bicarbonate. Serum IRT response to secretin stimulation was greater in 4 of the 5 patients with chronic pancreatitis with mild to moderate exocrine dysfunction than in the control group, suggesting an increased regurgitation of IRT into the blood stream by the pancreas, probably due to some degree of obstruction to pancreatic secretory flow in absence of severe acinar cell damage. Conversely, the response of serum IRT after secretin administration in 7 of the 8 patients with severe exocrine pancreatic deficiency was lower than in control subjects, probably because of the advanced distruction of the acinar pancreatic tissue. The response of serum IRT to secretin stimulation seems to vary following pancreatic function impairment and might reflect the degree of pancreatic exocrine dysfunction in chronic pancreatitis.

Adolescent↗