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Biomedical subjects

L Terenius

Publications and source records attributed to L Terenius.

At least 235 records · Page 13Linked to original sources
PubMed1985

Dynorphin peptides in human substantia nigra.

Stepwise processing of the prohormone for dynorphin-related peptides, proenkephalin B, may generate a large number of opioid peptides. It is therefore important to perform a chemical characterization of the immunoreactive dynorphin (ir-dyn) found in different tissues. In this study dynorphin peptides in human substantia nigra were characterized. Highly sensitive radioimmunoassays (RIA) directed against the C-terminals of dynorphin A (dyn A) and dynorphin B (dyn B) respectively, were used to measure the levels of dynorphin peptides. Tissue extraction was performed either with MeOH/0.1 M HCl (1/1) or 1 M HAc. Gel filtration on a Sephadex G-50 column revealed three peaks of ir-dyn B, the predominating one coeluting with synthetic dyn B. Ir-dyn A also appeared in three peaks, one of them (20-30%) coeluting with dyn A. The HAc extract contained much higher levels of ir-dyn B as compared to the MeOH/HCl extract, but approximately the same levels of ir-dyn A. Ion exchange separation of the HAc extract somewhat changed the size distribution pattern, with more ir coeluting with the synthetic peptides compared to other molecular weight forms.

Chromatography, Gel↗
PubMed1985

Enzyme-linked immunosorbent assay of substance P and its metabolite SP 1-7. A comparison with RIA.

We have investigated enzyme-linked immunosorbent assay (ELISA) as a possible alternative to radioimmunoassay (RIA) for the detection and measurement of the neuropeptide substance P (SP) and its metabolite substance P1-7. The sensitivities were higher with ELISA than with RIA utilizing the same antisera. The intra-assay and inter-assay variation in ELISA was 1% and 13% respectively. The higher sensitivities are in part due to the standard curves having less steep slopes, and in part to lower IC50s in the ELISA. Since there was a good correlation between peptide levels in biological samples as determined by ELISA and RIA respectively, ELISA might be considered an attractive alternative to RIA.

Animals↗
PubMed1985

Hallucinations in patients with major depression. Interactions between CSF monoaminergic and endorphinergic indices.

CSF levels of radioreceptorassayed endorphins Fraction I (EndFI, n = 92) and homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) (n = 118) were measured in patients with major depressive disorders according to Research Diagnostic Criteria (18% were psychotic; 11% hallucinated during the peak of the depressive episode). CSF measures (both "raw" variables and ranks) were uni- and multivariately correlated with both dichotomized and scored measures of hallucinations of any type. Hallucinations were statistically strongly associated with higher HVA levels, irrespective of prior medication with neuroleptics, and with the interactive product HVA X EndFI and the interactive ratio HVA/5-HIAA. Results suggest interactions between dopaminergic, serotonergic and endorphinergic neurotransmission being involved in the biochemical substrate of depressive hallucinatory episodes.

Adult↗
PubMed1985

A general procedure for analysis of proenkephalin B derived opioid peptides.

Tryptic digestion followed by radioimmunoassay for (Leu)enkephalin-Arg6 has been used in this study as a general method to detect the presence of all possible products containing the enkephalin sequence from the opioid peptide prohormone, proenkephalin B. Tissue extracts of human hypothalamus and pituitary were examined. Gel filtration was used to separate the different precursor products according to molecular weight. The elution profile was also monitored with highly sensitive radioimmunoassays for dynorphin A and dynorphin B, respectively. Immunoreactive dynorphin A appeared in three peaks with the approximate molecular weight of 1000, 2000 and 5000. Immunoreactive dynorphin B partly occurred in other peaks, 1500, 5000 and 10 000 dalton. Profiles obtained by measuring immunoreactive (Leu)enkephalin-Arg6 in all fractions from gel filtration after trypsin digestion showed a more complex pattern compared to the profiles of immunoreactive dynorphin A and dynorphin B. The major peaks coincided with dynorphin A and dynorphin B but high levels of immunoreactive (Leu)enkephalin-Arg6 were also generated from higher molecular weight regions (MW greater than 5000).

Chromatography, Gel↗
PubMed1985

Identification of substance P precursor forms in human brain tissue.

Substance P prohormones were identified in the caudate nucleus, hypothalamus, and substantia nigra of human brain. A polypeptide fraction of acidic brain extracts was fractionated on Sephadex G-50. The lyophilized fractions were sequentially treated with trypsin and a substance P-degrading enzyme with strong preference toward the Phe7-Phe8 and Phe8-Gly9 bonds. The released substance P(1-7) fragment was isolated by ion-exchange chromatography and quantitated by a specific radioimmunoassay. Confirmation of the structure of the isolated radioimmunoassay-active fragment was achieved by electrophoresis and HPLC. By using this enzymatic/radioimmunoassay procedure, two polypeptide fractions of apparent Mr 5000 and 15,000, respectively, were identified. The latter component was the major one of the two but was estimated to account for only about 5% of total substance P radioimmunoassay activity. Because it is of the size predicted from the nucleotide sequences of cDNA for substance P prohormones in bovine brain, the Mr 15,000 component may represent the full-length prohormone.

Amino Acid Sequence↗
PubMed1985

Measurement of substance P metabolites in rat CNS.

A procedure based on ion-exchange chromatography for chemical separation and radioimmunoassays for quantitation of substance P (SP), the SP(1-7), and C-terminal fragments, respectively, has been developed. The procedure allows the determination of these fragments in the presence of large (i.e., 50- to 100-fold) excess of parent compound. The chemical identity of isolated SP and fragments was studied with preparative electrophoresis on dilute agarose gel and with HPLC. The activity identified as SP(1-7) comigrated with the authentic standard whereas practically all activity isolated as C-terminal fragments comigrated with SP(5-11). The levels of C-terminal fragments in rat brain areas rich in SP and in spinal cord were 1-2% of those of parent compound. The levels of SP(1-7) were always higher, in the spinal cord markedly higher (three to five times). Postmortem storage of samples from brain and spinal cord indicated that SP(1-7) levels fell more rapidly than those of SP or C-terminal fragments.

Animals↗
PubMed1985

Appearance of the noradrenergic markers tyrosine hydroxylase and neuropeptide Y in cholinergic nerves of the iris following sympathectomy.

Selective autonomic denervations of the iris have been used to study the possible redistribution of adrenergic markers within adult nerve fiber systems and to reveal the cellular origin of a nonsympathetic fiber plexus induced to express such markers. The presence and distribution of fibers showing neuropeptide Y (NPY)- and tyrosine hydroxylase (TH)-like immunoreactivity was studied in the rat iris using stretch-prepared whole mounts. Normal irides contained a dense regular network of NPY-positive varicose fibers. Such fibers were regularly seen innervating blood vessels. The choroid membrane had a high number of fluorescent fibers. A similar, although slightly denser TH-positive fiber system was visualized in the iris. One or 2 days after surgical removal of the superior cervical ganglion, almost all NPY- and TH-positive fibers had disappeared, suggesting that most, if not all, NPY-positive fibers in the iris originate in the superior cervical ganglion. In irides from long-term sympathectomized animals, a high number of TH- and NPY-immunoreactive fibers had reappeared, while such irides were devoid of catecholamine-containing fibers, as evidenced by Falck-Hillarp histochemistry. The appearance of TH- and NPY-positive fibers in sympathetically denervated irides was clearly time dependent. The distribution of fluorescent fibers in irides from intact and sympathectomized animals showed obvious dissimilarities such as a lower fluorescence intensity and fewer varicose fibers in denervated irides. Furthermore, in irides from sympathectomized rats, TH- and NPY-positive fibers were not associated with blood vessels. Unilateral removal of the parasympathetic ciliary ganglion, which supplies the iris with cholinergic fibers, 3 days prior to sacrifice in animals bilaterally sympathectomized 1 month earlier, led to a drastic reduction in numbers of TH- and NPY-positive iris fibers on the ciliarectomized/sympathectomized side as compared to the sympathectomized-alone side. The present experiments thus suggest that adult cholinergic neurons in vivo are capable of expressing adrenergic characteristics under experimental conditions.

Adrenergic Fibers↗
PubMed1985

Evidence for differential localization of noradrenaline and neuropeptide Y in neuronal storage vesicles isolated from rat vas deferens.

Using the technique of homogenization and subsequent density gradient centrifugation combined with ultrastructural analysis, the subcellular localization of noradrenaline and neuropeptide Y (NPY) was studied in vas deferens of castrated male rats. Noradrenaline showed two peaks in the gradient: one major peak at low density and another at high density. Only one NPY peak was seen, which coincided with the high density peak of noradrenaline. Electron microscopic analysis revealed high proportions of small and large vesicles in the light and heavy fractions, respectively. The present results indicate a differential subcellular localization of noradrenaline and NPY in the noradrenergic nerve endings of vas deferens. Thus, small vesicles seem to contain only noradrenaline, whereas the large vesicles may contain both noradrenaline and NPY.

Animals↗
PubMed1984

Post-mortem analyses of neuropeptides in brains from sudden infant death victims.

The causative factors underlying SIDS are still unknown, but in recent years much interest has been focused on the central ventilatory control system. In this study, peptides which are known to affect respiration were examined in brains from SIDS victims and controls. The levels of Met-enkephalin and substance P were measured in cortex, medulla oblongata, pons and hypothalamus. Substance P1-7, substance P C-terminal fragments, Met-enkephalin-Lys6 and neuropeptide Y (NPY) were estimated in medulla oblongata. The substance P levels in the medulla oblongata from the SIDS victims were significantly elevated compared with the controls. No change, however, was observed in the Met-enkephalin levels, but a tendency to higher levels in the youngest infants was noticed. As substance P and enkephalins have opposite effects on respiration, their relative concentrations were calculated in each individual sample. The ratio was significantly higher in the medulla oblongata from the SIDS victims. The levels of NPY, substance P1-7, C-terminal fragments of substance P and Met-enkephalin-Lys6 were similar in both groups. A significant correlation between the NPY levels and age was observed, however.

Age Factors↗
PubMed1984

Substance P levels in various regions of the rat central nervous system after acute and chronic morphine treatment.

Substance P levels were measured in various CNS regions from rats treated acutely and chronically with morphine. There was no observable effect in the group treated with an acute dose of morphine (10 mg/kg) and sacrificed after 2 h. After 35 days chronic treatment with increasing doses of the drug, the rats were divided into three groups and sacrificed 2 h, 24 h and 7 days after the last injection. The substance P level was increased in the corpus striatum 2 h and 24 h and in the medulla oblongata and dorsal part of the spinal cord 2 h after withdrawal. Seven days after the last injection the levels had returned to normal in these areas. No effects were observed in the cerebral cortex, the hypothalamus or the ventral spinal cord at any time of measurement. Earlier studies have demonstrated that morphine inhibits release of substance P. The observed increase in tissue levels after long-term treatment is therefore interpreted as an accumulation of substance P in the neurons.

Animals↗
PubMed1984

Characterization of substance P(1-7) and (1-8) generating enzyme in human cerebrospinal fluid.

A substance P-hydrolyzing endopeptidase has been purified from a large quantity of human cerebrospinal fluid by ion exchange chromatography (DEAE-Sepharose CL-6B) and molecular sieving (Sephadex G-100 and Sephacryl S-200). The purification was monitored by measuring the conversion of synthetic substance P using a radioimmunoassay specific for its (1-7) fragment. The enzyme has an apparent molecular weight of 43,000. It cleaves predominantly at the Phe7-Phe8 and Phe8-Gly9 bonds but gives no or negligible conversion of the other tachykinins, neuromedin K and L (substance K).

Chromatography, Gel↗
PubMed1984

Effect of intranigral injections of dynorphin, dynorphin fragments and alpha-neoendorphin on rotational behaviour in the rat.

Peptides deriving from the proenkephalin B precursor were studied in the Ungerstedt rotational model after their unilateral injection into the substantia nigra. Dynorphin (DYN)-(1-17), DYN-(1-13) and DYN-(1-8) in 0.1-10 micrograms doses induced marked contralateral rotation. This effect was enhanced by subsequent systemic administration of D-amphetamine and blocked by previous treatment with naloxone. alpha-Neoendorphin produced similar effects although there was no evidence for dose-dependency. DYN-(6-17) which lacks opioid activity also produced contralateral rotation, which, however, was not naloxone reversible and D-amphetamine given subsequently did not induce asymmetric activation. Methionine enkephalin and leucine enkephalin, deriving from the proenkephalin A precursor were tested for comparison. Only the former produced weak contralateral rotation. GABA injected at the same site as DYN-(1-17) also induced contralateral rotation which was mimicked by nanogram doses of the gabaergic agonist muscimol. These findings suggest an interaction between peptides from the proenkephalin B precursor and nigro-striatal dopamine neurons as well as gabaergic striato-nigral efferents and/or interneurons.

Animals↗
PubMed1984

Distribution of neuropeptide immunoreactive nerve terminals within the subnuclei of the nucleus of the tractus solitarius of the rat.

The location of substance P, enkephalin and somatostatin (SRIF), and neurophysin II immunoreactive nerve terminals and preterminal processes in the caudal part of the nucleus of the tractus solitarius (nTS) was examined by the indirect immunofluorescence method for immunocytochemistry combined with cytoarchitectural identification of nuclear subgroups in the same tissue. In 22 Sprague-Dawley rats we examined 14-micrometers-thick serial sections of the dorsal medulla at levels from 1 mm caudal to 2 mm rostral to the obex. These sections were incubated with substance P, enkephalin, somatostatin, and neurophysin II antisera. All four peptides were examined in each case and five typical levels (two caudal and three rostral to the obex) were selected for comparison of terminal distribution between peptides. All sections were photographed under the fluorescence microscope and then counter-stained with cresyl violet. This method of analysis revealed distinct patterns of neuropeptide immunoreactivity in the subnuclei of the nTS that varied according to the level of the section. The nTS is responsible for integrating respiratory, cardiovascular (baroreceptor and cardiac), and gastrointestinal functions. The ventrolateral subnucleus (Vl)nTS, ventral subnucleus (v)nTS, interstitial subnucleus (ni)nTS, and intermediate subnucleus (nI)nTS are the major respiratory subnuclei with vlnTS and vnTS prominently associated with pulmonary afferents, ni associated with laryngeal afferents, and nI with tracheal afferents. The vlnTS, vnTS, and ni showed a moderate density of somatostatin-positive nerve terminals, scattered substance P and enkephalin immunoreactivity, and no neurophysin II-positive terminals. The nI showed moderate density of substance P immunoreactive nerve terminals. The subnuclei of the nTS receiving baroreceptor and chemoreceptor afferents--dorsolateral and dorsal (dl and d) subnuclei of nTS--showed scattered substance P immunoreactive nerve terminals. The commissural nucleus of nTS (ncom), which receives most of the cardiac afferents, showed a moderate density of enkephalin-positive immunoreactive nerve terminals. The medial subnucleus (m)nTS at levels rostral to the obex, the primary site for the termination of gastrointestinal afferents, showed substance P immunoreactivity in moderate amounts and weak immunoreactivity for all the other neuropeptides. An important result of these experiments was the observation that regions of the medulla adjacent to the nTS, i.e., the ventral parasolitarius region (vPSR), dorsal (d)PSR, and the periventricular region (PVR) showed the densest amounts of immunoreactive nerve terminals.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1984

Acupuncture mechanisms in rabbits studied with microinjection of antibodies against beta-endorphin, enkephalin and substance P.

Injection of protein-A purified antibodies against Met-enkephalin and beta-endorphin into the periaqueductal gray matter (PAG) was shown to decrease the analgesic effect of electroacupuncture (EA) in rabbits. Met-enkephalin antibodies were more potent than the beta-endorphin antibodies in causing a statistically-significant effect on electroacupuncture analgesia. Antibodies to Met-enkephalin were also active at the spinal level, whereas antibodies against beta-endorphin were without effect: this is in agreement with a rich enkephalinergic innervation and absence of beta-endorphin-containing fibres in the spinal cord. Substance P, the other neuropeptide of this study, also seems to be important in mediating effects of electroacupuncture. Injection of antibodies into the periaqueductal gray caused decrease of the effect of electroacupuncture whereas intrathecal administration of Fab-fragment substance P antibodies caused a marked potentiation. The demonstration of site specificity of the neuropeptides in mediating analgesia induced by electroacupuncture supports the validity of this experimental approach.

Acupuncture Therapy↗