[Utility of the medial region of pro-adrenomodulin for the detection of true bacteremia in elderly patients treated in the emergency department for suspected infection]

OBJECTIVE

The prediction of bacteremia in the emergency department (ER) is important for initial decision-making. The elderly population is a diagnosis challenge. The objective was to evaluate the accuracy of mid regional pro-adrenomedullin (MR-proADM) to identify true bacteremia (BV) in elderly patients attended in 3 hospital emergency departments.

METHODS

Observational study including patients ≥75 years of age or older attended in the ER for suspected infection in whom a blood culture (BC) was extracted. Sociodemographic, comorbidity, hemodynamic and analytical variables, biomarkers [MR-proADM, procalcitonin (PCT), C-reactive protein (CRP) and lactate] and final diagnosis were collected. The primary outcome was a true positive on a blood culture.

RESULTS

A total of 109 patients with a mean age of 83 (SD: 5.5) years were included. A final diagnosis of BV was obtained in 22 patients (20.2%). The independent variables to predict it were PCT (OR: 13.9; CI95%: 2.702-71.703; p=0.002), MR-proADM (OR: 4.081; CI95%: 1.026-16.225; p=0.046) and temperature (OR: 2.171; CI95%: 1.109-4.248; p=0.024). Considering the cut-off point for MR-proADM (2.13 mg/dl), a sensitivity (Se) of 73%, specificity (E) of 71%, a positive predictive value (PPV) of 39%, a negative predictive value (NPV) of 91%, a positive likelihood ratio (LHR+) of 2.53 and a negative likelihood ratio (LHR-) of 0.38; for PCT (0.76 mg/dl) a Se of 90%, E of 65%, PPV of 40%, NPV of 96%, LHR+ 2,64 and a LHR- of 0.14 were obtained. When combining both, a Se of 69%, E of 84%, PPV of 52%, NPV of 91%, LHR+ of 4.24 and LHR- of 0.38 were observed.

CONCLUSIONS

Elevated levels of PCT and MR-proADM were independently associated with an increased risk of BV and the combination of both improves the accuracy to identify these patients.

Trends and prediction of antimicrobial susceptibility in urinary bacteria isolated in European emergency departments: the EuroUTI 2010-2016 Study

Objectives

To assess recent trends in susceptibility to antibiotics among urinary isolates isolated in European emergency departments (EDs) and to identify isolates with a high (90% or more) predicted probability of susceptibility to fluoroquinolones or third-generation cephalosporins (3GCs).

Methods

In this cross-sectional study, we included urine cultures obtained from adult patients between 2010 and 2016 in 24 European EDs. Temporal trends were assessed using time-series analysis and multivariate logistic models. Multivariate logistic models were also used to predict susceptibility to fluoroquinolones or 3GCs from patient age and sex, year, month and ED.

Results

We included 88242 isolates. Time-series analysis found a significant increase in susceptibility to fluoroquinolones and no significant trend for susceptibility to 3GCs. Adjusting for patient age and sex, ED and organism, multivariate models showed that susceptibility to 3GCs decreased from 2014 to 2016, while susceptibility to fluoroquinolones increased in 2015 and 2016. Among isolates from 2016, multivariate models predicted high probability of susceptibility to fluoroquinolones in 11% of isolates (positive predictive value 91%) and a high probability of susceptibility to 3GCs in 35% of isolates (positive predictive value 94%).

Conclusions

Susceptibility of ED urinary isolates to fluoroquinolones increased from 2014, while susceptibility to 3GCs decreased from 2015. Predictive models identified isolates with a high probability of susceptibility to fluoroquinolones or 3GCs. The ability of such models to guide the empirical treatment of pyelonephritis in the ED remains to be determined.

The fibromyalgia patients would present higher levels of magnification that controls pain: A pilot study

Catastrophism is a variable of great importance in the study of pain. Catastrophism refers to a negative and exaggerated compared to the experience of pain, both real and anticipated mental perception (Sullivan, Bishop and Pivik, 1995; Sullivan et al., 2001). The current study to compare the levels of catastrophism in patients with and without fibromialgia. This study is cross-cutting and comparative. Twenty participants (M: 47.20; SD: 12.11) distributed as the following way:

– group 1: patients with fibromyalgia previously diagnosed through the American College of Rheumatology criteria (n = 10);

– group 2: Clinical depression, defined according to the DSM-5 (n = 5);

– group 3: healthy patients (n = 5) paired by age with the group of Fibromyalgia.

The PCS, a self-administered, was used to measure Catastrophism. Responses were summed to yield three different subscales: Rumination, Magnification and Helplessness. This instrument is validated in both experimental and clinical population (Van Damme, Crombez, Bijttebier, Gouber and Van Houdenhove, 2002; Edwards et al., 2006). A comparison among the three groups was established using one-way factor ANOVA. The results point out that patients with fibromyalgia have higher levels of magnification controls with depression and healthy group (P < 0.05). In contrast, although the average level of Catastrophism total presented a greater tendency in fibromyalgia patients no statistically significant differences were found. This is discussed in relation to the literature, a higher level of magnification to explain pain and maintaining the chronicity of the disease. It is important to consider the component catastrophism to have a multidimensional view of pain.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Neutron capture cross section of unstable 63Ni: implications for stellar nucleosynthesis

The 63Ni(n,γ) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from   kT=5-100  keV with uncertainties around 20%. Stellar model calculations for a 25M⊙ star show that the new data have a significant effect on the s-process production of 63Cu, 64Ni, and 64Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.

Cross-clade immunogenicity and safety of an AS03A-adjuvanted prepandemic H5N1 influenza vaccine in Hong Kong

OBJECTIVE

To present Hong Kong'Äìspecific data from a large Asian population (also involving Thailand, Singapore, and Taiwan) on safety and manufacturing consistency across four AS03(A)-adjuvanted H5N1 vaccine formulations in terms of immune response against the A/Vietnam/1194/2004 strain. Immunogenicity against the heterologous A/Indonesia/05/2005 strain was also assessed. NCT Number: 00449670.

DESIGN

Prospective, observer-blind study.

SETTING

Out-patient clinic of a tertiary hospital in Hong Kong.

PARTICIPANTS

A total of 360 subjects aged 18 to 60 years were randomised into six groups to receive two doses (21 days apart) of the study vaccine.

INTERVENTIONS

One of the four adjuvanted formulations (3.75 microgram H5N1 haemagglutinin [HA]+AS03(A)) of the vaccine (H5N1-AS03(A)) or one of the two non-adjuvanted (3.75 microgram H5N1 [HA]) formulations of the vaccine (H5N1-DIL).

MAIN OUTCOME MEASURES

Blood samples collected before vaccination and 21 days after each vaccine dose were analysed using haemagglutination-inhibition and neutralisation assays. Solicited, unsolicited, and serious adverse events were recorded.

RESULTS

Manufacturing consistency across all four vaccine formulations was demonstrated. After two doses, the AS03(A)-adjuvanted prepandemic influenza vaccine demonstrated high seroprotection rates against the A/Vietnam/1194/2004 strain (95.8%) and good immunogenicity against the heterologous A/Indonesia/05/2005 strain (45.7%), as compared to the non-adjuvanted vaccine (4.6% and 1.5%, respectively). The seroconversion rates induced by the adjuvanted formulations in terms of viral neutralising antibodies against the two strains were much higher than those induced by the non-adjuvanted formulations. There were no safety concerns for any of the adjuvanted vaccine formulations.

CONCLUSIONS

The AS03(A)-adjuvanted H5N1 prepandemic influenza vaccine demonstrated good immunogenicity and an acceptable safety profile in Hong Kong.

Roman Tunnelling Tool

The aim of this paper is to present an instrument that helps to create a subcutaneous path for central catheters used for hemodialysis, as well as a non traumatic internal introduction of Tesio's catheters and other systems (Dacron cap). We have designed a tunneling tool which consists of a solid but light weight hand set, connected to an extension that ends with an olive shape dilator to be connected to a trocar. Thus, precise tunneling is guaranteed through a non traumatic procedure, allowing exact anchorage of catheters.

Neuropharmacological profile of a selective sigma ligand, igmesine: a potential antidepressant

Igmesine is a selective sigma (sigma(1)) ligand that was reported to exert antidepressant action through an unknown mechanism of action. A number of neurochemical measures were taken in this study in efforts to understand its mode of action. Following 21-day drug treatments, the actions of igmesine on a number of neurochemical measures were investigated. Data obtained showed significant decreases in the densities of beta-adrenergic but not 5-HT(1A), sigma(1) and GABA(B) receptors in fluoxetine (18%), desipramine (DMI, 32%) and igmesine (20%)-treated groups when compared with control. Tyrosine hydroxylase (TH) activity was significantly (30-32%) reduced in all treated groups. Further, fluoxetine and DMI excluding the igmesine-treated groups showed 85 and 40% reductions in serotonin (5-HT) and noradrenaline (NE) neuronal uptake, respectively. Following acute treatment, igmesine lacked activity for monoamine oxidase (MAO) A or B (IC(50)>10 microM). In in vivo studies, at behaviorally active doses, igmesine showed weak effects on the NE uptake but lacked activity in altering 5-HT and DA synthesis or antagonizing selective drug-induced depletion of monoamine neuronal uptake. N-methyl-D-aspartate (NMDA)-induced increases in cGMP was blocked by igmesine indicating that igmesine may interfere with the NMDA receptor/nitric oxide synthase/cGMP pathway. Although it appears that part of the pharmacological actions of igmesine is mediated by the monoaminergic system, there is still need to explore other possible mechanisms of antidepressant action.

A study of the spread surface of polymeric dispersions of Eudragit

The rheology of non-Newtonian fluid systems is complex. Their experimental study is difficult because of the existence of many dependent variables. In the present work, a mathematical equation is proposed to calculate the spread surface from a simple viscosimetric study in a theoretical way. It was determined for multiple parameters. The spread surface has to be marked because of its direct relation to the shear stress; this fact enabled us to connect one variable dependent on the compression deformation with another dependent on the shear deformation. At the same time, the viscoelastic phenomenon can be evidenced by applying this mathematical equation.

[Granulomatous gastritis. Apropos of 2 cases]

We report two cases of granulomatous gastritis, one unexplained, one in the setting of Crohn's disease. Granulomatous gastritis is an uncommon entity. An etiopathogenetic diagnosis can be reached only by combining the morphological examination with clinical and laboratory investigations. Isolated granulomatous gastritis is a diagnosis of exclusion, distinct from Crohn's disease, sarcoidosis, infections, foreign bodies, malignancy or vasculitis.

Antinociceptive effect of (S)-N-desmethyl trimebutine against a mechanical stimulus in a rat model of peripheral neuropathy

Trimebutine (2-dimethylamino-2-phenylbutyl 3,4,5-trimethoxybenzoate, hydrogen maleate) relieves abdominal pain in humans. In the present study, the antinociceptive action of systemic (S)-N-desmethyl trimebutine, a stereoisomer of N-monodesmethyl trimebutine, the main metabolite of trimebutine in humans, was studied in a rat model of neuropathic pain produced by chronic constriction injury to the sciatic nerve. Mechanical (vocalization threshold to hindpaw pressure) stimulus was used. Experiments were performed two weeks after surgery when the pain-related behaviour has fully developed. (S)-N-desmethyl trimebutine (1, 3, 10 mg/kg s.c.) produced dose-dependent antinociceptive effects on the nerve-injured and the contralateral hindpaw. The effect of the lowest dose (1 mg/kg s.c.) of (S)-N-desmethyl trimebutine on the nerve-injured paw was equal to that seen after a ten time stronger dose on the contralateral paw. The effect of (S)-N-desmethyl trimebutine (1 mg/kg) was not naloxone reversible. The results suggest that systemic (S)-N-desmethyl trimebutine may be useful in the treatment of some aspects of neuropathic pain.

[Diabetes and urination disorders]

Diabetic neuropathy of can induce multi-organ dysfunction. The diabetes simultaneously has profound repercussions on gastrointestinal, sexual and erectile functions. One of the main sequelae of diabetic neuropathy is autonomic neuropathy affecting the vesicosphincteric control. The objective of this study was to review the epidemiological, clinical, laboratory and therapeutic data concerning voiding disorders observed in diabetes. Although the therapeutic management of an isolated voiding disorder in diabetics still remains symptomatic, it raises aetiological problems due to the comorbidity, particularly prostatic obstructive syndromes in men, pelvic dysfunction in women and ageing. Diabetic patients in renal failure also present specific vesicosphincteric disorders which are reviewed. Diabetic patients should be more systematically screened for the development of diabetic bladder disease, especially for associated factors which participate in its clinical expression. This implies extreme caution in the management of benign prostatic hyperplasia in the case of comorbidity, to avoid deteriorating a sometimes fragile detrusor-sphincter equilibrium. Diabetic detrusor hyperactivity must be better known in order to be more effectively detected. Pharmacological treatment of this condition raises problems related to detrusor hypocontractility also related to diabetic bladder disease. Clinical examination should be able to select those patients requiring further urodynamic studies in order to assess the individual detrusor-sphincter equilibrium. These investigations are required when surgical treatment of an associated urological or gynaecological disorder is considered.

The sigma-ligand (+)-pentazocine depresses M current and enhances calcium conductances in frog melanotrophs

Gramicidin-perforated patch clamp experiments and microfluorimetric measurements were performed to study the ionic mechanisms involved in the sigma-receptor-mediated stimulation of frog (Rana ridibunda) pituitary melanotrophs. The sigma-ligand (+)-pentazocine (50 microM) depressed a sustained outward K(+) current. The kinetic properties of this K(+) component, investigated by analyzing tail currents, were reminiscent of those of the M current (I(M)), with an activation threshold close to -60 mV, a -21-mV half-maximal activation potential, and two-component exponential deactivation kinetics at -90 mV. (+)-Pentazocine (20 microM) produced a 12-mV rightward shift of the activation curve and accelerated the deactivation rate of the tail current. It is also demonstrated that (+)-pentazocine (20 microM) reversibly increased both voltage-dependent calcium conductances and internal calcium level. Altogether, these results suggest that the sigma-receptor-induced modulation of I(M) and calcium currents likely underlies the increase of intracellular [Ca(2+)].

A-Current down-modulated by sigma receptor in frog pituitary melanotrope cells through a G protein-dependent pathway

Gramicidin perforated patch-clamp recordings were used to study the effects of two sigma 1 receptor ligands, (+)-N-cyclopropylmethyl-N-methyl-1, 4-diphenyl-1-ethyl-but-3-en-1-ylamine hydrochloride (JO 1784) and (+)-pentazocine, on the transient outward potassium current (IA) in cultured frog melanotrope cells. (+)-Pentazocine reversibly decreased the current amplitude in a dose-dependent manner. The effects of (+)-pentazocine were mimicked by JO 1784 and were markedly reduced by the sigma 1 receptor antagonist, N, N-dipropyl-2-[4-methoxy-3-2(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE 100). Inactivation rate of IA was best fitted with a double exponential function, yielding time constants of 23.7 and 112.5 ms. (+)-Pentazocine (20 microM) accelerated the current decay, decreasing the time constants to 10.7 and 59 ms, respectively. Current-voltage experiments revealed that (+)-pentazocine (20 microM) did neither modify the open-state I/V curves nor the voltage dependence of IA. However, (+)-pentazocine (20 microM) shifted the steady-state inactivation curve toward more negative potentials and increased the time constant of the time-dependent removal of inactivation. In whole-cell experiments, internal dialysis of guanosine-5'-O-(3-thiophosphate) (100 microM) irreversibly prolonged the response to (+)-pentazocine. In addition, cholera toxin pretreatment (1 microgram. ml-1; 12 h) suppressed the inhibition of IA by (+)-pentazocine (20 microM). It is concluded that in frog melanotrope cells, a cholera toxin-sensitive, G protein-dependent inhibition of IA through a sigma 1 receptor activation, at least partially, underlies the excitatory effect of sigma ligands.

Regional bone mineral density after orthotopic liver transplantation

OBJECTIVES

Although there is a fall in lumbar spine bone mineral density (BMD) after liver transplantation, little is known about femoral neck or total body BMD. Therefore we determined: (a) the proportion of patients with preexisting hepatic osteopenia before transplantation and (b) the effects of transplantation on global and regional BMD.

DESIGN

Retrospective analysis of BMD measurements of patients before and up to 2 years after liver transplantation.

METHODS

BMD was assessed by dual energy X-ray absorptiometry in 56 patients, before and at regular intervals after liver transplantation, for up to 24 months, to measure total body, lumbar spine (L2-L4) and femoral neck BMDs.

RESULTS

Pre-transplant, 23% of patients had osteoporosis (a negative Z score > 2). Paired data before and after transplantation revealed no change in total body BMD. However, there was a fall in lumbar spine BMD (1.04+/-0.03 to 1.02+/-0.03 g/cm2; P < 0.04) at 1 month after transplantation. The reduction in lumbar spine BMD was seen up to 12 months, BMD at 18-24 months being similar to pre-transplant values. Femoral neck BMD also fell (0.96+/-0.06 to 0.83+/-0.04 g/cm2; P < 0.03), but only after 6-9 months, thereafter remaining below pre-transplant values until the end of the follow-up period.

CONCLUSIONS

Although osteopenia is common in patients with liver disease, total bone density does not fall after transplantation. Nonetheless regional lumbar spine and femoral neck bone density does fall after transplantation with a risk period for femoral neck fracture which may extend for up to 2 years.

Sigma ligands stimulate the electrical activity of frog pituitary melanotrope cells through a G-protein-dependent inhibition of potassium conductances

We have investigated the effects of sigma ligands [1,3-di(2-tolyl)guanidine (DTG) and (+)-pentazocine] on the electrical activity of cultured frog pituitary melanotrope cells by using the patch-clamp technique. DTG and (+)-pentazocine (10 microM each) induced a reversible depolarization associated with an increase in membrane resistance and action potential firing. In voltage-clamp experiments, DTG and (+)-pentazocine elicited inward currents whose intensity augmented with membrane depolarization. The currents vanished or reversed between -90 and -100 mV, at values close to the K+ equilibrium potential (E(K)+ = -102 mV). DTG (2-500 microM) and (+)-pentazocine (0.2-200 microM) reduced the outward delayed rectifier K+ current [IK (V)] in a dose-dependent manner with EC50 of 64 and 37 microM, respectively. In contrast, naloxone (50 microM) and pirenzepine (10 microM) did not affect the sigma ligand-induced inhibition of IK (V). Addition of guanosine-5'-O-(3-thiophosphate) in the pipette solution irreversibly sustained the DTG-induced current whereas guanosine-5'-O-(2-thiodiphosphate) virtually suppressed the response. Cholera toxin-pretreatment (1 microgram/ml; 18 hr) abolished the inward current and the inhibition of IK (V) induced by sigma ligands. In contrast, pretreatment with pertussis toxin (1 microgram/ml; 18 hr) had no effect. Taken together, these data indicate that DTG and (+)-pentazocine activate the electrical activity of cultured frog melanotrope cells by reducing both a tonic K+ current and a voltage-dependent [IK (V)] K+ conductance through the activation of a cholera toxin-sensitive G-protein.

Effects of orthotopic liver transplantation on body composition

AIMS/BACKGROUND

The effects of orthotopic liver transplantation on body composition are unclear. We aimed to assess changes in body composition after transplantation using dual energy x-ray absorptiometry and total body potassium.

METHODS

Dual energy x-ray absorptiometry and total body potassium counting to assess muscle mass were performed in 55 patients before and up to 24 months after liver transplantation and the results expressed as paired data before and at time intervals after transplantation.

RESULTS

The results showed that total body weight fell by 3.6 +/- 1.3 kg (p < 0.02) at 1 month, with a maximal fall in lean tissue mass at 2-5 months of 4.8 +/- 1.2 kg (p < 0.003). Thereafter, no change in lean tissue mass was recorded, although there were increases at 12 and 24 months of total body weight (11.5 +/- 2.4 kg, 7.8 +/- 3.1 kg; p < 0.03, respectively) and fat mass (12.9 +/- 2.2 and 10.5 +/- 2.7 kg; p < 0.003). A fall in total body potassium was seen at 1 month (118 +/- 12 mmol; p < 0.003) and 2-5 months (176 +/- 9.9 mmol; p < 0.03), which mirrored the fall in lean mass.

CONCLUSIONS

After liver transplantation there is an initial fall in body weight due to a loss of lean mass. Lean mass does not recover after transplantation, although there is an increase in fat mass that leads to the observed increase in total body weight.

Risk factors for loss of lean body mass after liver transplantation

BACKGROUND

After liver transplantation there is a fall in lean body mass.

AIMS

To determine the risk factors for this fall in lean body mass using univariate and subgroup analyses.

PATIENTS AND METHODS

Dual energy X-ray absorptiometry was performed in 36 patients (12 with Child-Pugh Class A, 20 with Class B and 4 with Class C disease) before and up to 24 months after liver transplantation. Univariate and sub-group comparative analyses were performed to assess possible risk factors for the fall in lean body mass post-transplantation.

RESULTS

The pre-transplantation serum albumin inversely correlated with the fall lean body mass at 1 month (r = 0.55; p < 0.009) and at 6-9 months (r = 0.51; p < 0.05) post-transplantation. A positive correlation between the fall in lean body mass and: (i) cumulative dose of steroids administered at 2-5 months (r = 0.57; p < 0.05) and (ii) length of hospital stay after transplantation (r = 0.52; p < 0.05) were also observed. Neither the severity or presence of cholestatic liver disease pre-transplant, nor acute cellular rejection post-transplant were risk factors for a fall in lean mass.

DISCUSSION

A hypercatabolic state post-transplant (represented by low albumin pre-transplantation), immobility, lack of exercise and steroid induced catabolism of muscle may cause the observed fall in lean mass after liver transplantation. Earlier transplantation of patients with better nutritional status and the use of low dose steroid immunosuppressive regimens may prevent the observed fall in lean body mass after transplantation.

Characterization of vasoactive intestinal peptide/pituitary adenylate cyclase-activating peptide receptors in human benign hyperplastic prostate

Vasoactive intestinal peptide (VIP) is an important member of the group of neuropeptides that appears to be involved in the regulation of prostatic growth and function. Here we studied VIP receptors in membranes from human benign hyperplastic prostate. Accordingly to observations in rat prostatic membranes, [125I]VIP binding to human prostatic membranes suggested two classes of binding sites with high Kd = 0.22 nM) and low (Kd = 37.7 nM) affinities. VIP bound in human and rat membrane preparations to a common VIP/pituitary adenylate cyclase-activating peptide (PACAP) receptor, as VIP, PACAP-27, and PACAP-38 were equipotent for competition of [125I]VIP binding. A PACAP-preferring receptor appears to be expressed in human prostate, since [125I]PACAP binding was displaced with more potency by PACAP than by VIP, and a messenger RNA corresponding to type I PACAP receptor was found. Cross-linking experiments suggested a VIP receptor of about 71 kDa in human and 52 kDa in rat prostates. The binding of [125I]VIP to membranes and the labeling of the bands observed after electrophoresis were competitively inhibited by GTP, suggesting the coupling of VIP receptors to a G protein. Moreover, after solubilization and cross-linking, we observed a 120-kDa band that corresponded to the VIP receptor-alpha s association. VIP stimulated adenylyl cyclase activity in a dose-dependent manner, but the potency and/or the efficacy of VIP were lower in all human preparations studied than in rat prostatic membranes. In conclusion, this study clearly demonstrates the expression of VIP/PACAP common receptors associated with alpha s protein in human prostate and suggests that these neuropeptides could play an important and complex role in the physiology and pathophysiology of this human gland.

Autoradiographic evidence for the modulation of in vivo sigma receptor labeling by neuropeptide Y and calcitonin gene-related peptide in the mouse brain

Peptides of the neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) families have been reported to modulate, in vivo, sigma receptor systems in the mouse and rat hippocampal formation. In an attempt to determine if these interactions were specific to the hippocampal formation, quantitative ex vivo autoradiography was used with (+)(-)[3H]SKF 10,047 as sigma ligand after i.c.v. injections of various NPY and CGRP peptides. High levels of specific (+)(-)[3H]SKF 10,047 labeling were concentrated in various cranial nerve nuclei, whereas lower but still significant amounts of labeling were seen in the cortex, hippocampus, various hypothalamic nuclei, red nucleus, substantia nigra, central gray and cerebellum. In all brain areas enriched with specific (+)(-)[3H]SKF 10,047/sigma labeling, the Y1 receptor subtype agonist [Leu31Pro34]-NPY, as well as peptide YY and rCGRP beta, inhibited, to a rather similar extent, (+)(-)[3H]SKF 10,047 labeling. The Y2 receptor agonist NPY13-36 had no effect in any of the regions studied. These results extend findings obtained in the hippocampal formation and demonstrate the existence of in vivo modulatory effects of NPY and CGRP-related peptides on sigma sites throughout the mouse brain.

In vivo modulation of sigma receptor sites by calcitonin gene-related peptide in the mouse and rat hippocampal formation: radioligand binding and electrophysiological studies

Possible interactions between sigma (sigma) receptor sites and calcitonin gene-related peptides (CGRP) were investigated using receptor subtype-related analogues and fragment in in vivo [3H](+)SKF 10 047/sigma binding in the hippocampus, and electrophysiological recording of the N-methyl-D-aspartate (NMDA)-induced activation of CA3 pyramidal neurons, two well-established sigma assays. In both paradigms, CGRP and the agonist [Cys(ACM)2,7]hCGRPalpha modulated sigma systems. In vivo binding experiments demonstrated that CGRP and [Cys(ACM)2,7]hCGRPalpha inhibited 25-40% of specific [3H](+)SKF 10 047 labelling in the mouse hippocampal formation while the purported antagonist hCGRP8-37 was inactive. The specificity of this modulation was demonstrated further by the lack of effect of other vasoactive peptides, including the atrial natriuretic peptide, substance P, and its N-terminal fragment, substance P1-7. In the CA3 subfield of the rat dorsal hippocampus, hCGRP alpha decreased (up to 61%) the NMDA-induced activation of the pyramidal neurons. Conversely, the linear analogue [Cys(ACM)2,7]hCGRP alpha enhanced (by 85%) the NMDA-induced activation of CA3 pyramidal neurons, while the antagonistic fragment hCGRP8-37 had no effect. Haloperidol, a high-affinity sigma receptor ligand, inhibited by 90% the in vivo [3H](+)SKF 10 047 labelling, and prevented the modulation of the NMDA-induced activation by hCGRP alpha and [Cys(ACM)2,7]hCGRP alpha. It thus appears that CGRP can modulate sigma-related systems in the hippocampal formation.