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PubMed1982

Metabolic and endocrine changes in spinal cord injury: III. Less quanta of sensory input plus bedrest and illness.

This is the fourth article (Part III) of a 4-part series which provides a comprehensive review and analysis of the pertinent literature published over the last 25 years on the metabolic and endocrine consequences of spinal cord injury (SCI). The studies on SCI patients reviewed in this article include reports and investigations concerning plasma ACTH, plasma and urine corticosteroids and their diurnal variations at rest and during stress, of fasting values of TSH and growth hormone, thyroxine, testosterone, and of urinary skin collagen metabolites and urinary tryptamine. Information from articles reviewed here is organized under the following headings: Problems studied, Methods of investigation and results, Conclusions, Summary of results, Discrepancies, Areas of research needed, and Practical clinical implications. Highlights of pertinent data contained in the original articles are organized in tables to facilitate direct comparisons between similar studies and between data on healthy and subjects with spinal cord injuries.

Adrenal Cortex Hormones↗
PubMed1983

Comparison of monoamine oxidase in golden hamster islets and insulinoma.

We compared the properties of monoamine oxidase (MAO) in hamster islets and insulinomas. The tryptamine concentration at which the monoamine oxidase velocity was half maximal (Km) was higher in islets than insulinomas; the maximal velocity (Vmax) of monoamine oxidase was greater in islets than insulinomas. Both islet and insulinoma are more sensitive to inhibition by pargyline than clorgyline. After pargyline administration the monoamine oxidase activity of insulinoma returns faster than activity of islets. This may occur because both synthesis of new MAO in pre-existing cells and formation of new cells occurs in the insulinoma.

Adenoma, Islet Cell↗
PubMedDate not supplied

Synthesis and pharmacological properties of N-arylpiperazine-N'-alkylindanes.

Ten new compounds, N-aryl substituted piperazinealkylindanes, have been synthesized. The most active one 1-(2-[4-(3-chlorophenyl)-1-piperazinyl]-ethyl)-indane (compound 9), displayed evident central serotoninolytic properties in the 5-hydroxytryptamine (5-HTP) head twitch test in mice, as well as in the tryptamine convulsions test and the quipazine-stimulated hind paw flexor reflex test in rats.

5-Hydroxytryptophan↗
PubMed1981

The dose of nicorandil in men predicted from the inhibition of MAO activity by organic nitrates.

The effect of N-(2-hydroxyethyl)-nicotinamide nitrate ester (nicorandil) on rat heart monoamine oxidase (MAO) was investigated in vitro. MAO activity was assayed by the isotopic method with 14C-tryptamine as substrate. Nicorandil significantly inhibited MAO activity of rat heart mitochondria. The effect of nicorandil on the enzymatic kinetics of MAO of rat heart mitochondria indicates that the anti-anginal drug acts as a competitive inhibitor of MAO. The inhibitor constant (Ki) of nicorandil was 4.93 mmol/l. The Ki of nicorandil was fitted to the formula derived from the relationship between the Ki values of glyceryl trinitrate, erythrytol tetranitrate, mannitol hexanitrate and isosorbide dinitrate and the dose of these drugs recommended to relieve anginal pain in patients. The dose of nicorandil was 0.071 mmol (15.0 mg at a time). This value agreed with the clinical dose for patients (10--20 mg at a time).

Animals↗
PubMed1984

Pharmacological effects of deltamethrin on the central nervous system.

Pharmacological exploration of the central nervous system carried out by means of a series of tests confirms the affinity of 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid alpha-cyano-3-phenoxybenzyl ester (delta-methrin) for the nervous system and reveals the following activities of deltamethrin: Deltamethrin has no neuroleptic or sedative action. It inhibits motility, sense of balance and inquisitiveness of treated animals. It potentiates chloral-induced hypnotic action but not that of pentobarbital. Not only does it have no antagonistic action on convulsivant agents: electric shock, pentetrazol, strychnine, but it stimulates their toxicity and prolongs the convulsive seizures. The fact that deltamethrin acts on different convulsivant agents (i.e. pentetrazol and strychnine) with various sites of action suggests that its activity is located in both the cortical and the medullary centres. Deltamethrin reveals the latent toxicity of tryptamine used in the non-toxic dose range; this predicts that deltamethrin might have an IMAO (inhibitor of monoamine oxidase) activity. Experiments carried out under the conditions adopted showed that deltamethrin acts on various sites.

Amphetamine↗
PubMed1978

[Identification of serotonin receptors in several grape snail neurons].

Four types of unit responses to iontophoretical serotonin (5-hydroxytrytamine) application were obtained on the ventral surface of the visceral ganglion in the hibernating Helix pomatia. The responses differed in sign, duration, latent period, reaction to serotonin antagonists (d-tubocurarine, tryptamine, neostigmine). It seems that every type of unit response to serotonin is associated with a definite type of serotonin receptors. A scheme of serotonin receptor distribution in the studied neurons is presented.

Animals↗
PubMed1980

The acute and chronic effect of 5-methoxytryptamine on selected members of a primate social colony.

The acute and chronic effect of 5-methoxytryptamine (5-MeOT), a structural analogue of known tryptamine hallucinogens and a substance found in mammalian brain, on nonhuman primate behavior was studied in a social colony of four Stumptail macaques. In the first study, dose-dependent behavioral changes induced by 5-MeOT were determined with the administration of seven acute doses to each animal. At higher doses, 10-20 mg/kg, 5-MeOT induced two abnormal or "emergent" behaviors, body shakes and limb jerks. 5-MeOT also induced a dose-dependent reduction in normal social and solitary behavior of treated animals suggesting that this drug has sedative properties. The second study examined the effect of once daily administration of 5-MeOT, 10 mg/kg, for 5 days. During this time, tolerance developed to both 5-MeOT-induced body shakes and limb jerks, but failed to develop to the reduction in social and solitary behaviors. Since body shakes and limb jerks are behaviors characteristically induced in this species by hallucinogens, these results suggest that 5-MeOT may possess hallucinogenic properties. However, this effect may be weak and may only occur after large doses since large doses of 5-MeOT were required to induce a relatively small number of body shakes and limb jerks in monkeys when compared to potent hallucinogens such as LSD and 5-MeODMT.

5-Methoxytryptamine↗
PubMedDate not supplied

The effect of budipine on the central serotoninergic system.

Budipine, a new potential antiparkinsonian drug, did not affect or--in higher doses--inhibited the flexor reflex in spinal rats, having no influence on LSD- or fenfluramine-induced flexor-reflex stimulation. It did not affect the body temperature either of the rat kept at a high ambient temperature or of the rabbit in a normothermic surroundings. It weakened fenfluramine hyperthermia in heat-adapted rats, but not in rabbits. Only in high doses budipine weakened tryptamine-induced clonic convulsions of rat forepaws. Budipine partially prevented fenfluramine-induced depletion of whole brain 5-hydroxytryptamine. The above results show that budipine demonstrates some properties of 5-HT uptake inhibitors.

Animals↗
PubMedDate not supplied

[New date on biogenic amines of developming sea urchin embryos].

Using two fluorimetric techniques, identification and assay of indolylalkylamines have been made in sea urchin eggs and embryos. It was shown that serotonin-like substance of embryonic and adult specimens is not usually homogeneous and consists at least of two components, the main of them being presented by tryptamine or one of its derivatives with the replaced group at amino nitrogen. Serotonin is also present at all the developmental stages investigated although its concentrations are significantly lower. It is suggested that these substances are involved into regulatory processes during early embryogenesis.

Animals↗
PubMed1980

Comparison of some conformationally rigid benzylamine analogs as substrates for rabbit lung N-methyltransferase.

7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline hydrochloride (SK&F 64139) and 8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine hydrochloride (LY134046) were found to be excellent substrates for rabbit lung N-methyltransferase using S-adenosyl-L-methionine-methyl-14C as the methyl donor. These conformationally rigid analogs of benzylamine had Km values lower than, and Vmax values at least as high as, those of the physiologically occurring amines usually considered as the best substrates for this enzyme (tryptamine, N-methyltryptamine and serotonin). Since LY134046 and SK&F 64139 have high affinity as competitive inhibitors of norepinephrine N-methyltransferase, some similarity in the active site of these two enzymes is suggested.

Amines↗
PubMed1978

Significant events in the rehabilitation process: the spinal cord patient's point of view.

The purpose of this study was to identify and evaluate significant events in the hospital phase of rehabilitation. Ten patients with high-level spinal cord injuries were studied 5 days a week for the entire length of their hospital stays (mean stay--109 days). Methods of identifying significant events through tape-recorded, daily logs were developed and found reliable at a level of 0.08 or higher. These events, with a net of days surrounding them, were grouped into categories, and evaluated against a control group of days--in which no significant events were identified. Four measures of depressive affect were evaluated: (1) a self report measure, (2) ratings by the hospital staff, (3) behavioral measure of verbal output, and (4) an endocrine measure, the 24-hour output of urinary tryptamine. Seventy-three percent of reactions on the dependent measures of depressive-elative affect were in the direction predicted by patient evaluations. Significant events were rank ordered according to their average rank on the 4 measures of depressive affect. There are advantages to a longitudinal, multimeasure approach to the rehabilitation career of chronically ill or injured patients.

Adaptation, Psychological↗
PubMed1994

Pharmacological characterization of LY293284: A 5-HT1A receptor agonist with high potency and selectivity.

(-)-LY293284, (-)-4R-6-acetyl-4-(di-n-propylamino)1,3,4,5- tetrahydrobenz[c,d]indole, is a conformationally restricted tryptamine derivative with an acetyl group serving as a protophilic substitution for the hydroxyl in serotonin (5-HT). In ligand displacement studies, LY293284 had a Ki of 0.07 nM for the 5-HT1A receptor but no affinity for other monoaminergic receptors within 3 orders of magnitude. LY293284 was evaluated in in vivo models, which have been used as markers for presynaptic and postsynaptic 5-HT1A receptor activity. LY293284 decreased hypothalamic 5-hydroxyindoleacetic acid levels (ED50, 2.9 micrograms/kg s.c.) and dorsal raphe serotonergic neuron firing rate (ED50, 0.08 micrograms/kg s.c.), which are accepted indices of presynaptic activity. LY293284 also induced a reduction in body temperature in rats (ED50, 3.6 micrograms/kg s.c.), which was blocked by pretreatment with (+/-)-pindolol. Hypothermic responses of rats to 5-HT1A agonists have had both pre- and postsynaptic characteristics in previous studies. The ED50 values for 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) in these tests were 15 to 45 times higher than those observed for LY293284. In models for postsynaptic activity, the ED50 for LY293284 for elevating serum corticosterone levels was 9.7 micrograms/kg s.c. and the minimum effective doses to induce lower lip retraction and flat posture were 3 micrograms/kg s.c. For comparison, the same indices obtained for 8-OH-DPAT were 222.4 and 100 micrograms/kg, respectively. The 5-HT syndrome responses induced by LY293284 were also attenuated by pretreatment with (+/-)-pindolol. LY293284 was 10 times more potent than 8-OH-DPAT in a drug discrimination test that used pigeons trained to identify 8-OH-DPAT. In sexual behavior tests with male rats, LY293284 induced a maximal reduction in ejaculatory latency at 0.01 micrograms/kg s.c., which was approximately 10 times higher potency than 8-OH-DPAT. In the pigeon conflict model for anxiolytic activity, LY293284 was 100 times more potent than 8-OH-DPAT in increasing punished responding. In the rat forced swim model for antidepressant-like activity, LY293284 was 30 and 35 times more potent than 8-OH-DPAT in decreasing immobility time and defecation rate. These studies have demonstrated that LY293284 is a highly selective and extremely potent 5-HT1A receptor agonist and represents a useful pharmacological tool for studying 5-HT1A receptor-mediated effects.

Animals↗
PubMed1993

Further evidence that the guinea pig tracheal contractile serotonergic receptor is a 5-hydroxytryptamine2 receptor: use of 5-methyltryptamine and dipropyl-5-carboxamidotryptamine.

The guinea pig tracheal contractile serotonergic receptor shows pharmacological similarity to both 5-hydroxytryptamine2 (5-HT2) and 5-hydroxytryptamine1C (5-HT1C) receptors. The present in vitro study utilizes 5-methyltryptamine (5-MT), a high-affinity 5-HT1C receptor ligand, and dipropyl-5-carboxamidotryptamine (DP-5-CT), a low-affinity 5-HT1C receptor ligand, as tools to probe the role of 5-HT1C vs. 5-HT2 receptors in tracheal contractility. Both tryptamines contracted trachea with lower potency (-log EC50 < 5) than 5-HT (-log EC50 = 6.98). Maximum contraction to both 5-MT and DP-5-CT was only 50 to 80% of the maximum response to 5-HT, suggesting that these compounds were partial agonists relative to 5-HT. Guinea pig tracheal contraction to 5-HT, 5-MT and DP-5-CT was inhibited by 1-(1-naphthyl)piperazine (1-NP, 30 nM). The apparent antagonist dissociation constants (KB) for 1-NP were similar when 5-HT (-log KB, K = 8.70 +/- 0.17) or 5-MT (- log KB = 8.40 +/- 0.12) were used as agonists. Although 1-NP also blocked tracheal contraction to DP-5-CT, solubility limitations with DP-5-CT did not permit calculation of a KB value for 1-NP. Nevertheless, these data indicate that 5-MT and DP-5-CT interact with the same receptor as 5-HT. As antagonists, both 5-MT and DP-5-CT inhibited tracheal contraction to 5-HT, indicating interaction with the same receptor as 5-HT and confirming partial serotonergic agonist activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Biogenic amines derived from tryptophan in systemic and cutaneous scleroderma.

Blood levels of serotonin (5-HT) and urinary excretion of 5-hydroxyindole-acetic acid (5-HIAA), tryptamine (T), and indole-acetic acid (IAA) were determined in 39 cases of systemic scleroderma and in 7 cases of very severe cutaneous scleroderma. The T/IAA ratio was normal and serotonin elevated in mild and rather severe acrosclerosis alike, i.e. in systemic scleroderma with pronounced vascular involvement. The T/IAA ratio was increased and serotonin normal in severe acroscleroderma, representing an intermediate form or transition to diffuse scleroderma, in severe diffuse scleroderma, and in severe cutaneous scleroderma. The T/IAA ratio and serotonin level were both elevated in a few cases of systemic scleroderma and in severe generalized morphea with concomitant vascular changes. The findings suggest impaired monoamine oxidase (MAO) activity in scleroderma with consequent accumulation in the organism of biogenic amines derived from tryptophan. An increased T/IAA ratio seems to be of prognostic significance in scleroderma, suggesting an adverse course of the disease.

Colorimetry↗
PubMed1977

Observations on the monamine oxidase activity of rat vasa deferentia, major blood vessels and human saphenous vein.

Monoamine oxidase (MAO) activity was characterized using whole tissue homogenates and kynuramine as the substrate. In rat vasa deferentia, kynuramine deamination was differentially inhibited by clorgyline, less so by deprenyl and not at all by pargyline. These studies, and mixed substrate experiments with tryptamine, proved that kynuramine is a substrate for MAO types A and B. Experiments made with rat abdominal aorta and inferior vena cava disclosed clorgyline-sensitive and resistant MAO activity, the latter being inhibited by semicarbazide but not by deprenyl or pargyline. No semicarbazide-sensitive species of MAO was found in human saphenous vein which also differed from the rat vasculature in that the predominant MAO activity was of the B type. It is concluded that kynuramine is also a good substrate for clorgyline-resistant enzymes and that rat vasculature may be a poor model for predicting deaminating mechanisms in human venous tissue.

Adult↗
PubMedDate not supplied

[Changes in substrate specificity of brain mitochondrial monoamine oxidase].

Mitochondrial monoamine oxidase isolated from bovine brain stem and purified to electrophoretic homogeneity contained 15 SH groups per mole (100000) of protein. The enzyme deaminated tyramine, p-nitro-beta-phenylethylamine, dopamine, 5-hydroxytryptamine, tryptamine but did not deaminate histamine, GABA or spermidine. Oxidation of 9-II SH groups in the MAO by air oxygen was accompanied by appearance of the properties to deaminate histamine or GABA. This qualitative alteration (transformation) in catalytic properties of the enzyme was readily reversed by treatment with reducing agents (dithiothreitol or GSH). No structural alterations detectable by electrophoresis in polyacrylamide gel were observed in course of the qualitative reversible modifications in catalytic activity of MAO. The qualitative alterations in substrate specificity were also initiated by treatment with H2O2 of the monoamine oxidases tightly bound with membrane structures of mitochondria from bovine brain stem.

Animals↗
PubMed1996

Enzymology of indole alkaloid biosynthesis in Catharanthus roseus.

Indole alkaloids in Catharanthus roseus have been in focus because of their medicinal value. These alkaloids consist of an indole moiety provided by tryptamine and a terpenoid portion provided by the secologanin. The most important catharanthus alkaloids are vinblastine (VLB), vincristine (VCR) and ajmalicine. VLB and VCR are clinically useful anticancer agents whereas ajmalicine is used for the treatment of circulatory diseases. VCR and VLB are the most expensive because of their low abundance in the plant, and are formed by the coupling of monomeric indole alkaloids vindoline and catharanthine, catalysed by peroxidases. The pathway that lead to monomeric indole alkaloids involves more than 20 enzymes of which 16 enzymes have been isolated and characterized biochemically, and only three at the molecular level. The present state of knowledge on enzymes and genes involved in indole alkaloid biosynthesis and various aspects of their regulation has been discussed.

Alkaloids↗
PubMedDate not supplied

[The mechanism of the reaction forming tryptophanyl-tRNA, catalyzed by tryptophan:tRNA-ligase].

The rates of tryptophanyl-tRNA formation catalyzed by beef pancreas tryptophanyl-tRNA synthetase were measured in a concentration range of each substrate (tryptophan, ATP and yeast tRNATrp) and also in the presence of various concentrations of substrate analogues (tryptamine and alpha,beta-methylene analogue of ATP) concentrations. The data obtained were compared with the kinetic equations which described various possible mechanisms of the reaction. The comparison of the mechanisms was based on the calculation of relative probabilities of each hypothesis the efficiency of which was demonstrated earlier. The calculations have shown that two mechanisms according to which the intermediate enzyme-aminoacyl-adenylate complex formation involves the enzyme-aminoacyl-tRNA complex are the most probable ones.

Adenosine Triphosphate↗