The Impact of MNRI Therapy on the Levels of Neurotransmitters Associated with Inflammatory Processes

The neurotransmitter levels of representatives from five different diagnosis groups were tested before and after participation in the MNRI®-Masgutova Neurosensorimotor Reflex Intervention. The purpose of this study was to ascertain neurological impact on (1) Developmental disorders, (2) Anxiety disorders/OCD (Obsessive Compulsive Disorder), PTSD (Post-Traumatic Stress disorder), (3) Palsy/Seizure disorders, (4) ADD/ADHD (Attention Deficit Disorder/Attention Deficit Disorder Hyperactive Disorder), and (5) ASD (Autism Spectrum Disorder) disorders. Each participant had a form of neurological dysregulation and typical symptoms respective to their diagnosis. These diagnoses have a severe negative impact on the quality of life, immunity, stress coping, cognitive skills, and social assimilation. This study showed a trend towards optimization and normalization of neurological and immunological functioning, thus supporting the claim that the MNRI method is an effective non-pharmacological neuromodulation treatment of neurological disorders. The effects of MNRI on inflammation have not yet been assessed. The resulting post-MNRI changes in participants' neurotransmitters show significant adjustments in the regulation of the neurotransmitter resulting in being calmer, a decrease of hypervigilance, an increase in stress resilience, behavioral and emotional regulation improvements, a more positive emotional state, and greater control of cognitive processes. In this paper, we demonstrate that the MNRI approach is an intervention that reduces inflammation. It is also likely to reduce oxidative stress and encourage homeostasis of excitatory neurotransmitters. MNRI may facilitate neurodevelopment, build stress resiliency, neuroplasticity, and optimal learning opportunity. There have been no reported side effects of MNRI treatments.

Catecholamine metabolism in paraganglioma and pheochromocytoma: similar tumors in different sites?

Pheochromocytoma (PHEO) and paraganglioma (PGL) are catecholamine-producing neuroendocrine tumors that arise respectively inside or outside the adrenal medulla. Several reports have shown that adrenal glucocorticoids (GC) play an important regulatory role on the genes encoding the main enzymes involved in catecholamine (CAT) synthesis i.e. tyrosine hydroxylase (TH), dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT). To assess the influence of tumor location on CAT metabolism, 66 tissue samples (53 PHEO, 13 PGL) and 73 plasma samples (50 PHEO, 23 PGL) were studied. Western blot and qPCR were performed for TH, DBH and PNMT expression. We found a significantly lower intra-tumoral concentration of CAT and metanephrines (MNs) in PGL along with a downregulation of TH and PNMT at both mRNA and protein level compared with PHEO. However, when PHEO were partitioned into noradrenergic (NorAd) and mixed tumors based on an intra-tumoral CAT ratio (NE/E >90%), PGL and NorAd PHEO sustained similar TH, DBH and PNMT gene and protein expression. CAT concentration and composition were also similar between NorAd PHEO and PGL, excluding the use of CAT or MNs to discriminate between PGL and PHEO on the basis of biochemical tests. We observed an increase of TH mRNA concentration without correlation with TH protein expression in primary cell culture of PHEO and PGL incubated with dexamethasone during 24 hours; no changes were monitored for PNMT and DBH at both mRNA and protein level in PHEO and PGL. Altogether, these results indicate that long term CAT synthesis is not driven by the close environment where the tumor develops and suggest that GC alone is not sufficient to regulate CAT synthesis pathway in PHEO/PGL.

How to prevent alcoholic liver disease

Betaine supplements of alcoholic beverages are proposed to prevent the development of alcoholic liver disease in patients that abuse alcohol. This recommendation is based on the observation of studies where it has been shown in binge drinking and chronic ethanol feeding animal models that betaine prevents liver injury resulting from high blood alcohol levels. The basic observation is that betaine added to ethanol being ingested increases the elimination rate of blood alcohol, which prevents the blood alcohol levels (BALs) from reaching high levels. The mechanism of how betaine does this is postulated to be that betaine causes the increase in the elimination rate by increasing the metabolic rate which generates NAD the rate limiting cofactor of alcohol oxidation by ADH. Betaine does this most likely by supporting the methylation of norepinephrine to form epinephrine by phenylethanolamine N-methyltransferase. Epinephrine is 5 to 10-fold more active than norepinephrine in increasing the metabolic rate.

Partial blockade of nicotinic acetylcholine receptors improves the counterregulatory response to hypoglycemia in recurrently hypoglycemic rats

Recurrent exposure to hypoglycemia can impair the normal counterregulatory hormonal responses that guard against hypoglycemia, leading to hypoglycemia unawareness. This pathological condition known as hypoglycemia-associated autonomic failure (HAAF) is the main adverse consequence that prevents individuals with type 1 diabetes mellitus from attaining the long-term health benefits of tight glycemic control. The underlying molecular mechanisms responsible for the progressive loss of the epinephrine response to subsequent bouts of hypoglycemia, a hallmark sign of HAAF, are largely unknown. Normally, hypoglycemia triggers both the release and biosynthesis of epinephrine through activation of nicotinic acetylcholine receptors (nAChR) on the adrenal glands. We hypothesize that excessive cholinergic stimulation may contribute to impaired counterregulation. Here, we tested whether administration of the nAChR partial agonist cytisine to reduce postganglionic synaptic activity can preserve the counterregulatory hormone responses in an animal model of HAAF. Compared with nicotine, cytisine has limited efficacy to activate nAChRs and stimulate epinephrine release and synthesis. We evaluated adrenal catecholamine production and secretion in nondiabetic rats subjected to two daily episodes of hypoglycemia for 3 days, followed by a hyperinsulinemic hypoglycemic clamp on day 4. Recurrent hypoglycemia decreased epinephrine responses, and this was associated with suppressed TH mRNA induction (a measure of adrenal catecholamine synthetic capacity). Treatment with cytisine improved glucagon responses as well as epinephrine release and production in recurrently hypoglycemic animals. These data suggest that pharmacological manipulation of ganglionic nAChRs may be promising as a translational adjunctive therapy to avoid HAAF in type 1 diabetes mellitus.

Fetal glucocorticoid synthesis is required for development of fetal adrenal medulla and hypothalamus feedback suppression

During pregnancy, fetal glucocorticoid is derived from both maternal supply and fetal secretion. We have created mice with a disruption of the Cyp11a1 gene resulting in loss of fetal steroid secretion but preserving the maternal supply. Cyp11a1null embryos have appreciable although lower amounts of circulating corticosterone, the major mouse glucocorticoid, suggesting that transplacental corticosterone is a major source of corticosterone in fetal circulation. These embryos thus provide a means to examine the effect of fetal glucocorticoids. The adrenal in Cyp11a1 null embryos was disorganized with abnormal mitochondria and oil accumulation. The adrenal medullary cells did not express phenylethanolamine N-methyltransferase and synthesized no epinephrine. Cyp11a1 null embryos had decreased diencephalon Hsd11b1, increased diencephalon Crh, and increased pituitary Pomc expression, leading to higher adrenocorticotropin level in the plasma. These data indicate blunted feedback suppression despite reasonable amounts of circulating corticosterone. Thus, the corticosterone synthesized in situ by the fetus is required for negative feedback suppression of the hypothalamus-pituitary-adrenal axis and for catecholamine synthesis in adrenal medulla.

Adrenal Epinephrine and the Regulation of Pulmonary Surfactant Release in Neonatal Rabbits

Adrenergic mechanisms influence surfactant metabolism; however the nature and importance of catechol-mediated regulation is unclear. We designed experiments to assess the role of endogenous adrenal epinephrine (E) synthesis in neonatal alveolar surfactant release. We administered the experimental adrenal epinephrine synthesis inhibitor SKF 29661 to pregnant rabbits to reduce fetal adrenal E content. Surfactant release was measured as total alveolar phosphatidylcholine (PC) content recovered by a thorough alveolar wash performed on animals sacrificed at birth and at 1 h of age. At a maternal dose of 100 mg/kg/day, SKF 29661 caused a 57% reduction in fetal adrenal E content (p less than .01), which was associated with a 40% reduction in alveolar PC at birth and a 23% reduction in alveolar PC at 1 h of age (p less than .01). Moreover, adrenal E correlated positively with total alveolar PC content (p less than .001). These results suggest that in the neonatal period, the ability of the fetal adrenal gland to synthesize E for secretion plays a role in the regulation of pulmonary surfactant release.

Cardiac epinephrine synthesis and ischemia-induced myocardial epinephrine release

OBJECTIVE

Phenylethanolamine-N-methyltransferase (PNMT), the enzyme that synthesizes epinephrine (EPI) from norepinephrine (NE) in the adrenal gland, is present in extra-adrenal tissues including heart. Ischemia evokes an excessive NE accumulation in the myocardial interstitial spaces. Therefore, cardiac PNMT activity with high NE levels may contribute to cardiac EPI synthesis and release evoked by ischemia.

METHODS

We measured dialysate EPI levels in the left ventricle of anesthetized rabbits using a cardiac microdialysis technique. The dialysate EPI level served as an index of the myocardial interstitial EPI level. Locally administered NE-induced dialysate EPI responses were measured. The left circumflex coronary artery was occluded for 60 min and the dialysate EPI and NE levels in the ischemic region were measured. Coronary occlusion-induced EPI responses were compared with and without administration of a PNMT inhibitor (SKF29661) in the presence and absence of desipramine (catecholamine transport blocker).

RESULTS

Local administration of NE (250, 2500 ng/ml) increased the EPI levels to 734+/-125 and 2088+/-367 pg/ml respectively. These increases in dialysate EPI were suppressed by the PNMT inhibitor. Acute myocardial ischemia significantly increased the EPI levels to 3607+/-1069 pg/ml in the ischemic region, and these were suppressed by the PNMT inhibitor (1417+/-581 pg/ml). The pretreatment with desipramine suppressed ischemia-induced EPI release, which did not differ with (725+/-155 pg/ml) and without administration of a PNMT inhibitor (743+/-172 pg/ml).

CONCLUSION

The cardiac PNMT in the left ventricle is capable of synthesizing EPI with markedly elevated NE levels in the myocardial interstitial space.

Beta-adrenergic receptor agonists delay while antagonists accelerate epithelial wound healing: evidence of an endogenous adrenergic network within the corneal epithelium

Wound healing is a complex and well-orchestrated biological process. Corneal epithelial cells (CECs) must respond quickly to trauma to rapidly restore barrier function and protect the eye from noxious agents. They express a high level of beta2-adrenergic receptors but their function is unknown. Here, we report the novel finding that they form part of a regulatory network in the corneal epithelium, capable of modulating corneal epithelial wound repair. Beta-adrenergic receptor agonists delay CEC migration via a protein phosphatase 2A-mediated mechanism and decrease both electric field-directed migration and corneal wound healing. Conversely, beta-adrenergic receptor antagonists accelerate CEC migration, enhance electric field-mediated directional migration, and promote corneal wound repair. We demonstrate that CECs express key enzymes required for epinephrine (beta-adrenergic receptor agonist) synthesis in the cytoplasm and can detect epinephrine in cell extracts. We propose that the mechanism for the pro-motogenic effect of the beta-adrenergic antagonist is blockade of the beta2-adrenergic receptor preventing autocrine catecholamine binding. Further investigation of this network will improve our understanding of one of the most frequently prescribed class of drugs.

[Participation of annexins in Ca2+-regulated secretion of catecholamines]

Secretion of catecholamines by adrenal medulla chromaffin cells occurs after their stimulation by nicotine or depolarization of plasma membrane. Adrenal medulla secrets mostly noradrenaline and adrenaline, both having pleyotropic action in the organism. Central role in regulation of exocytosis of catecholamines play calcium ions. Their intracellular concentration increases as a cell response to stimulus and creates signal to start secretion. Moreover, annexins are known to participate in regulation of biological membrane dynamics during intracellular transport processes, however their participation in secretion is less established then in endocytosis. Among twelve annexin subfamilies (AnxA1-A11 i A13) expressed in mammalian organisms only involvement of AnxA2 and AnxA6 in endocytosis is well documented. Some data suggests that annexins may play important functions also in Ca2+-regulated catecholamine secretion.

Metabolic consequences of exercise-associated autonomic failure

Type I diabetes mellitus patients who tightly control blood glucose levels toward normal have increased frequency of hypoglycemia, a major barrier to physical activity. This article presents the hypothesis that dysfunctional autonomic regulation of metabolism after recent bouts of exercise or hypoglycemia contributes to exercise-induced hypoglycemia in these patients.

Identification of phenylethanolamine N-methyltransferase gene expression in stellate ganglia and its modulation by stress

Phenylethanolamine N-methyltransferase (PNMT, EC 2.1.1.28) is the terminal enzyme of the catecholaminergic pathway converting noradrenaline to adrenaline. Although preferentially localized in adrenal medulla, evidence exists that PNMT activity and gene expression are also present in the rat heart, kidney, spleen, lung, skeletal muscle, thymus, retina and different parts of the brain. However, data concerning PNMT gene expression in sympathetic ganglia are still missing. In this study, our effort was focused on identification of PNMT mRNA and/or protein in stellate ganglia and, if present, testing the effect of stress on PNMT mRNA and protein levels in this type of ganglia. We identified both PNMT mRNA and protein in stellate ganglia of rats and mice, although in much smaller amounts compared with adrenal medulla. PNMT gene expression and protein levels were also increased after repeated stress exposure in stellate ganglia of rats and wild-type mice. Similarly to adrenal medulla, the immobilization-induced increase was probably regulated by glucocorticoids, as determined indirectly using corticotropin-releasing hormone knockout mice, where immobilization-induced increase of PNMT mRNA was suppressed. Thus, glucocorticoids might play an important role in regulation of PNMT gene expression in stellate ganglia under stress conditions.

Epinephrine biosynthesis: hormonal and neural control during stress

1. Stress contributes to the pathophysiology of many diseases, including psychiatric disorders, immune dysfunction, nicotine addiction and cardiovascular illness. Epinephrine and the glucocorticoids, cortisol and corticosterone, are major stress hormones. 2. Release of epinephrine from the adrenal medulla and glucocorticoids from the adrenal cortex initiate the biological responses permitting the organism to cope with adverse psychological, physiological and environmental stressors. Following its massive release during stress, epinephrine must be restored to replenish cellular pools and sustain release to maintain the heightened awareness and sequelae of responses to re-establish homeostasis and ensure survival. 3. Epinephrine is regulated in part through its biosynthesis catalyzed by the final enzyme in the catecholamine pathway, phenylethanolamine N-methyltransferase (E.C. 2.1.1.28, PNMT). PNMT expression, in turn, is controlled through hormonal and neural stimuli, which exert their effects on gene transcription through protein stability. 4. The pioneering work of Julius Axelrod forged the path to our present understanding of how the stress hormone and neurotransmitter epinephrine, is regulated, in particular via its biosynthesis by PNMT.

Mode of binding of methyl acceptor substrates to the adrenaline-synthesizing enzyme phenylethanolamine N-methyltransferase: implications for catalysis

Here we report three crystal structure complexes of human phenylethanolamine N-methyltransferase (PNMT), one bound with a substrate that incorporates a flexible ethanolamine side chain (p-octopamine), a second bound with a semirigid analogue substrate [cis-(1R,2S)-2-amino-1-tetralol, cis-(1R,2S)-AT], and a third with trans-(1S,2S)-2-amino-1-tetralol [trans-(1S,2S)-AT] that acts as an inhibitor of PNMT rather than a substrate. A water-mediated interaction between the critical beta-hydroxyl of the flexible ethanolamine group of p-octopamine and an acidic residue, Asp267, is likely to play a key role in positioning the side chain correctly for methylation to occur at the amine. A second interaction with Glu219 may play a lesser role. Catalysis likely occurs via deprotonation of the amine through the action of Glu185; mutation of this residue significantly reduced the kcat without affecting the Km. The mode of binding of cis-(1R,2S)-AT supports the notion that this substrate is a conformationally restrained analogue of flexible PNMT substrates, in that it forms interactions with the enzyme similar to those observed for p-octopamine. By contrast, trans-(1S,2S)-AT, an inhibitor rather than a substrate, binds in an orientation that is flipped by 180 degrees compared with cis-(1R,2S)-AT. A consequence of this flipped binding mode is that the interactions between the hydroxyl and Asp267 and Glu219 are lost. However, the amines of inhibitor trans-(1S,2S)-AT and substrate cis-(1R,2S)-AT are both within methyl transfer distance of the cofactor. These results suggest that PNMT catalyzes transfer of methyl to ligand amines only when "anchor" interactions, such as those identified for the beta-hydroxyls of p-octopamine and cis-AT, are present.

Identification of the prolactin-releasing peptide-producing cell in the rat adrenal gland

Prolactin-releasing peptide (PrRP) is a novel peptide found in bovine hypothalamus as an endogenous ligand of an orphan G-protein-coupled receptor (hGR3). It is known that PrRP is widely distributed and plays roles in the central nervous system (CNS). In particular, PrRP acts as a neurotransmitter that mediates stress and activates the hypothalamo-pituitary-adrenal axis. On the other hand, only a few studies have so far been performed on PrRP in peripheral tissues. Among peripheral tissues, appreciable levels of PrRP are found only in the adrenal gland; however, the PrRP-producing cells in the adrenal gland have not been identified. In this study, we detected PrRP mRNA in the rat adrenal medulla. So, we tried to identify the PrRP-producing cells in primary culture cells of the adrenal medulla. We found immunopositive PrRP cells among the cultured cells from the adrenal gland, but not in the adrenal gland tissue, by means of immunocytochemistry. The PrRP immunopositive cells were double positive for tyrosine hydroxylase (TH) and for phenylethanolamine N-methyltransferase (PNMT), which indicates that PrRP may be produced in a part of the adrenaline cells in the adrenal gland. This is the first report that PrRP is produced in the adrenaline-containing cells of the adrenal gland.

m-CPP, a 5-HT2C Receptor Agonist That Modifies the Perfusion Pressure of the Hindquarter Vascular Bed of Anesthetized Rat

In the present work we studied the actions of the intra-arterial administration of meta-chlorophenylpiperazine (m-CPP - a 5-HT(2C) receptor agonist) in the hindquarters of the anesthetized rat. The lowest doses used (0.001, 0.01, 0.1, 0.25 and 0.5 microg/kg) induced vasodilatation whereas the highest doses produced vasoconstriction (1, 6.25, 12.5 and 25 microg/kg). Both vasodilatation and vasoconstriction were inhibited by the 5-HT(1,2 )receptor antagonist methiothepin, whereas the 5-HT(2 )receptor antagonist ritanserin blocked only the vasoconstrictor responses. 1-[4-(1-Adamantanecarboxamido)butyl]-4-(2-methoxyphenyl)piperazine (a 5-HT(1A) receptor antagonist) and ICI 118,551 (a beta(2)-receptor antagonist) failed to modify the vasodilator responses of m-CPP. Both BRL 15572 (a 5-HT(1D) receptor antagonist) and GR 55562 (a 5-HT(1B) receptor antagonist) only partially inhibited this action. Our data reveal that m-CPP induces the 5-HT(1 )and/or non-specific vasodilator effect and 5-HT(2) vasoconstrictor effects in the hindquarter vascular bed of the rat.

Stressor Specificity and Effect of Prior Experience on Catecholamine Biosynthetic Enzyme PhenylethanolamineN-Methyltransferase

The specific activation of two components of the sympathoadrenal system (adrenomedullary and sympathoneural) by various stressors was recently described. The aim of this work was to investigate changes in catecholamine (CA) biosynthetic enzyme phenylethanolamine N-methyltransferase (PNMT) gene expression, protein level, and activity in the adrenal medulla of rats after a single or repeated exposure to various homotypic or novel heterotypic stressors. Immobilization for 2 h (IMO), cold 4 degrees C (COLD), administration of insulin 5I U (INS), or 2-deoxyglucose 500 mg/kg (2DG) were used as stressors. Plasma epinephrine (EPI) and norepinephrine (NE) levels clearly showed that these stressors specifically activate the aforementioned systems. A single exposure to IMO, COLD, INS, or 2DG induced increases in PNMT mRNA levels in the adrenal medulla. Besides PNMT mRNA, repeated exposure to IMO also elevated activity and protein levels of the enzyme; however, chronic cold exposure did not show PNMT changes compared to control animals at room temperature. PNMT gene expression was also investigated in rats adapted to repeated immobilization stress or to chronic cold exposure after a single exposure to various heterotypic novel stressors. Cold-adapted rats responded to heterotypic novel stressors (IMO, INS) by exaggerated responses of PNMT mRNA levels compared to responses in naive rats exposed to the same stressors at room temperature. Immobilization-adapted rats did not show exaggerated responses of PNMT mRNA after exposure to novel stressors. Therefore, observed differences in plasma CA and adrenomedullary mRNA levels suggest a specific regulation of CA release, synthesis, and gene expression of CA biosynthetic enzymes, which depends on the quality of the stressor. Exposure of adapted rats to novel stressors induces exaggerated responses, but this process also depends on the specificity of the stressor used. Different stressors regulate PNMT gene expression by specific mechanisms especially in chronically stressed rats. These mechanisms remain to be elucidated. It is the ability of the long-term stressed organism to respond differently to novel heterotypic stressors that we consider an important adaptive phenomenon of catecholaminergic systems in rats.

An assay for determination of rat adrenal catechol-O-methyltransferase activity: comparison of spontaneously hypertensive rats and Wistar?Kyoto rats

A method has been developed for measurement of catechol-O-methyltransferase (COMT) activity in the rat adrenal gland. Epinephrine, synthesized in the adrenal gland, was used as substrate, and its enzymatic product, metanephrine, was quantified by high-performance liquid chromatography (HPLC) with fluorescence detection. The method has sufficient precision and accuracy. Soluble (S) and membrane-bound (MB) COMT activity in Wistar-Kyoto (WKY) rats was 20.7 +/- 3.5 and 18.6 +/- 3.4 pmol min(-1) mg(-1) protein (n = 5), respectively. To clarify the role of adrenal COMT in blood-pressure regulation, S and MB COMT activity in spontaneously hypertensive rats were determined. Respective activity was 18.6 +/- 3.4 and 17.0 +/- 1.1 pmol min(-1) mg(-1) (n = 5), which is similar to that in WKY rats. This finding suggests that COMT in the adrenal gland might not be related to blood pressure regulation.

Sleep deficit and stress hormones in helicopter pilots on 7-day duty for emergency medical services

INTRODUCTION

Helicopter-based emergency medical services in Germany operate from sunrise to sunset, requiring up to 15.5 h of continuous duty during the summer months for pilots, who work for seven consecutive days. Because of concerns regarding the safety of this procedure with respect to pilot fatigue and stress, the German Ministry of Transport asked our laboratory to investigate the risks involved.

METHODS

There were 13 pilots (mean age 38 yr) who were studied in the summer months for 2 d before, 7 d during, and 2 d after their duty cycle. Measured variables included sleep duration and quality, subjective fatigue, and heart rate, as well as 24-h excretion levels of stress hormones.

RESULTS

During actual helicopter operations, maximum heart rates did not exceed 120 bpm. Over the 7-d duty period, mean sleep duration decreased from 7.8 h to 6 h or less, resulting in a cumulative sleep loss of about 15 h. Mean levels of excreted adrenalin, noradrenalin, and cortisol increased significantly by 50 to 80%; cortisol and noradrenalin excretion also remained elevated for the two post-duty days.

CONCLUSIONS

Although the actual flights did not cause critical physiological responses, the acute and accumulated sleep deficit led to incomplete recuperation between duty hours and induced elevated stress indicators. It was, therefore, recommended that the duty cycle be amended as follows: 1.) enforce a 10-h rest period and at least an 8-h sleep opportunity per day; 2.) modify the duty period to allow no more than 3 consecutive rest periods of reduced sleep opportunities (8.5 h); and 3.) follow duty with several days that offer unrestricted sleep opportunities.

Nanomolar Inhibitors of CNS Epinephrine Biosynthesis: (R)-(+)-3-Fluoromethyl-7-(N-substituted aminosulfonyl)-1,2,3,4-tetrahydroisoquinolines as Potent and Highly Selective Inhibitors of Phenylethanolamine N-Methyltransferase

A series of (R)-(+)-3-fluoromethyl-7-(N-substituted aminosulfonyl)-1,2,3,4-tetrahydroisoquinolines has been synthesized and evaluated as inhibitors of PNMT and for their affinity for the alpha(2)-adrenoceptor. Compounds (R)-8 and (R)-9 are remarkably potent and selective inhibitors of PNMT and are predicted to penetrate the blood-brain barrier on the basis of their calculated log P values. Conformational analysis and docking studies were performed in order to examine why the (R)-enantiomer of these 3-fluoromethyl-7-(N-substituted aminosulfonyl)-1,2,3,4-tetrahydroisoquinolines is more potent than the (S)-enantiomer and to determine the likely bound ring conformer of the (R)-enantiomer. It appears that the (R)-enantiomer participates in a water-mediated hydrogen bond in which the (S)-enantiomer cannot. The likely favored ring conformation for (R)-3-fluoromethyl-7-(N-substituted aminosulfonyl)-1,2,3,4-tetrahydroisoquinolines in the PNMT active site is similar to the ring conformation of (R)-5a as determined by gas-phase ab initio calculations.

Molecular recognition of sub-micromolar inhibitors by the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase

The crystal structures of human phenylethanolamine N-methyltransferase in complex with S-adenosyl-l-homocysteine (7, AdoHcy) and either 7-iodo-1,2,3,4-tetrahydroisoquinoline (2) or 8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine (3, LY134046) were determined and compared with the structure of the enzyme complex with 7 and 7-aminosulfonyl-1,2,3,4-tetrahydroisoquinoline (1, SK&F 29661). The enzyme is able to accommodate a variety of chemically disparate functional groups on the aromatic ring of the inhibitors through adaptation of the binding pocket for this substituent and by subtle adjustments of the orientation of the inhibitors within the relatively planar binding site. In addition, the interactions formed by the amine nitrogen of all three inhibitors reinforce the hypothesis that this functional group mimics the beta-hydroxyl of norepinephrine rather than the amine. These studies provide further clues for the development of improved inhibitors for use as pharmacological probes.

Expression of tyrosine hydroxylase in lymphocytes and effect of endogenous catecholamines on lymphocyte function

OBJECTIVES

To comprehend the changes and significance of the endogenous catecholamines in the immune system, we explored the synthesis of catecholamines by lymphocytes in various lymphoid organs and in different activated states, and the effect of the endogenous catecholamines synthesized by lymphocytes on the function of the lymphocytes themselves.

METHODS

Immunohistochemistry for lymphoid organs (mesenteric lymph nodes, spleen and thymus) and lymphocytes was used to observe their expression of tyrosine hydroxylase (TH), an initial rate-limiting enzyme of the catecholamine synthesis. The contents of catecholamines, including norepinephrine (NE), dopamine (DA) and epinephrine (E), in lymphocytes were tested by means of high-performance liquid chromatography with electrochemical detection. Western blot was used to examine the character and relative quantity of TH-stained protein in lymphocytes, lymph nodes and adrenal medullary tissue. The effect of alpha-methyl-P-tyrosine (alpha-MT), an inhibitor of TH activity, on concanavalin A (Con A)-induced interleukin-2 (IL-2) production was determined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay.

RESULTS

TH-positive cells were found in the three examined lymphoid organs, but the lymph nodes had the highest and the thymus had the lowest density. Both TH expression and the contents of NE, DA and E in the Con A-activated lymphocytes were markedly increased in comparison with those in the nonactivated lymphocytes. A band with TH immunoreactivity was seen in the extracts from either Con A-activated lymphocytes or nonactivated cells and the molecular weight of the protein was 59.4 +/- 0.3 kD. However, the relative quantity of the protein was notably higher in the activated lymphocytes than in the nonactivated cells. As a positive control, a similar band of TH immunoreactivity in the adrenal medullary tissue was also obtained. Alpha-MT at the doses of 10(-11), 10(-10) and 10(-9) M was found to significantly facilitate the Con A-induced IL-2 production.

CONCLUSIONS

These results suggest that lymphocytes can synthesize catecholamines and their synthesis levels may increase in the activated state, and that endogenous catecholamines synthesized by the lymphocytes can regulate the function of the lymphocytes themselves.

Defect in epinephrine production in children with craniopharyngioma: functional or organic origin?

Despite pituitary hormone replacement, patients with craniopharyngioma often complain of fatigue. They may have deficient control of catecholamine secretion caused by hypothalamic lesion. Another hypothesis is a functional defect in catecholamine production through either glucocorticoid deficiency because high intraadrenal glucocorticoid concentration is necessary for epinephrine synthesis or unrecognized hypoglycemia, which can intrinsically alter epinephrine secretion. We measured catecholamine response to insulin-induced hypoglycemia and orthostasis, and 24-h urinary catecholamine excretion, in 16 children with craniopharyngioma (patients) and 27 sex- and age-matched short children. We also studied the influence of a 4-fold increase in the usual daily dose of hydrocortisone on catecholamine excretion (50 vs. 12 mg/m(2) of body surface area) in the glucocorticoid-deficient patients. Last, we compared 24-h continuous sc glucose in patients and 10 sex- and age-matched healthy children. The results are expressed as medians (25th, 75th). For a similar blood glucose nadir after insulin administration, peak plasma epinephrine in response to hypoglycemia was lower in patients vs. controls [420 (120, 715) vs. 730 (460, 1200) ng/liter, P < 0.01], whereas peak plasma norepinephrine was higher [390 (280, 550) vs. 270 (180, 280) ng/liter, P < 0.05]. Catecholamine response to orthostasis did not differ between groups. Urinary epinephrine was significantly lower in patients (P < 0.001), whereas urinary norepinephrine was similar. The extent of epinephrine deficiency correlated with neither tumor size nor hypothalamic involvement. A 4-fold higher hydrocortisone dose did not correct the defective epinephrine excretion in the glucocorticoid-deficient patients. Last, the 24-h sc glucose values were similar between patients and controls. In conclusion, children with craniopharyngioma have a defect in epinephrine but not norepinephrine production. There is no proof of a univocal origin, either organic or functional. Whether abnormal catecholamine secretion alters glucose level during fasting or acute illness, or hampers adaptation to exercise, requires further studies.

Prospective double-blind randomized study of the effects of four intravenous fluids on platelet function and hemostasis in elective hip surgery

A prospective randomized double-blind study was performed to determine the effects of three colloids, Haemaccel, Gelofusine and albumin, and also saline on platelet activation, platelet aggregation (induced by adenosine diphosphate (ADP), epinephrine, collagen) platelet agglutination by ristocetin and other hemostatic variables in 55 patients undergoing primary unilateral total hip replacement. The fluids were administered according to normal clinical practice and assessments were made immediately before, at the end, and 2 h after the end of surgery. Surgery was accompanied by thrombin generation (increases in thrombin/antithrombin III complex, prothrombin F1 +2 fragment) platelet activation (betaTG) and compromised coagulation. Generally, the platelet activation appeared to result in platelet desensitization and brought about a persistent reduction in platelet aggregation to ADP and epinephrine, irrespective of the fluid used. Additionally, Haemaccel and Gelofusine inhibited ristocetin-induced platelet agglutination and albumin inhibited collagen-induced platelet aggregation. Gross inhibitory effects of Haemaccel that had been predicted from an earlier in vitro study did not occur. Particular fluids had selective additional effects on the hemostatic system. Albumin infusion served to maintain plasma albumin at normal concentrations postsurgery. The two gelatin preparations, Haemaccel and Gelofusine, maintained plasma viscosity. All three colloids led to a transient increase in activated partial thromboplastin time postsurgery and also a transient fall in the concentration of factor VIII, which were accompanied by a transient increase in bleeding time, but there was no measurable increase in blood loss. Inhibition of platelet aggregation by certain colloids may provide additional protection against the increased thrombotic risk in patients following major surgery.

The Effects of Music Listening after a Stressful Task on Immune Functions, Neuroendocrine Responses, and Emotional States in College Students

The purpose of this study was to examine the effects of listening to high-uplifting or low-uplifting music after a stressful task on (a) immune functions, (b) neuroendocrine responses, and (c) emotional states in college students. Musical selections that were evaluated as high-uplifting or low-uplifting by Japanese college students were used as musical stimuli. Eighteen Japanese subjects performed stressful tasks before they experienced each of these experimental conditions: (a) high-uplifting music, (b) low-uplifting music, and (c) silence. Subjects' emotional states, the Secretory IgA (S-IgA) level, active natural killer (NK) cell level, the numbers of T lymphocyte CD4+, CD8+, CD16+, dopamine, norepinephrine, and epinephrine levels were measured before and after each experimental condition. Results indicated low-uplifting music had a trend of increasing a sense of well-being. High-uplifting music showed trends of increasing the norepinephrine level, liveliness, and decreasing depression. Active NK cells were decreased after 20 min of silence. Results of the study were inconclusive, but high-uplifting and low-uplifting music had different effects on immune, neuroendocrine, and psychological responses. Classification of music is important to research that examines the effects of music on these responses. Recommendations for future research are discussed.

Chromaffin cell function and structure is impaired in corticotropin-releasing hormone receptor type 1-null mice

Corticotropin-releasing hormone (CRH) is both a main regulator of the hypothalamic-pituitary-adrenocortical axis and the autonomic nervous system. CRH receptor type 1 (CRHR1)-deficient mice demonstrate alterations in behavior, impaired stress responses with adrenocortical insufficiency and aberrant neuroendocrine development, but the adrenal medulla has not been analyzed in these animals. Therefore we studied the production of adrenal catecholamines, expression of the enzyme responsible for catecholamine biosynthesis neuropeptides and the ultrastructure of chromaffin cells in CRHR1 null mice. In addition we examined whether treatment of CRHR1 null mice with adrenocorticotropic hormone (ACTH) could restore function of the adrenal medulla. CRHR1 null mice received saline or ACTH, and wild-type or heterozygous mice injected with saline served as controls. Adrenal epinephrine levels in saline-treated CRHR1 null mice were 44% those of controls (P<0.001), and the phenylethanolamine N-methyltransferase (PNMT) mRNA levels in CRHR1 null mice were only 25% of controls (P <0.001). ACTH treatment increased epinephrine and PNMT mRNA level in CRHR1 null mice but failed to restore them to normal levels. Proenkephalin mRNA in both saline- and ACTH-treated CRHR1 null mice were higher than in control animals (215.8% P <0.05, 268.9% P <0.01) whereas expression of neuropeptide Y and chromogranin B did not differ. On the ultrastructural level, chromaffin cells in saline-treated CRHR1 null mice exhibited a marked depletion in epinephrine-storing secretory granules that was not completely normalized by ACTH-treatment. In conclusion, CRHR1 is required for a normal chromaffin cell structure and function and deletion of this gene is associated with a significant impairment of epinephrine biosynthesis.