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Cites the decision of the U.S. National Weather Service to adopt the apparent temperature index as a summertime measure of sultriness. Design of the index to describe the combined effects of temperature and humidity on human comfort; Attribution of the system of measure by R.G. Steadman; Use of the apparent temperature to approximate the temperature of current conditions and its effect on an average person.

Background and Purpose: Using an in-house bioinformatics programme, we identified and synthesized a novel nonapeptide, H-Pro-Pro-Thr-Thr-Thr-Lys-Phe-Ala-Ala-OH. Here, we have studied its biological activity, in vitro and in vivo, and have identified its target in the brain., Experimental Approach: The affinity of the peptide was characterized using purified whole brain and striatal membranes from guinea pigs and rats . Its effect on behaviour in rats following intra-striatal injection of the peptide was investigated. A photoaffinity UV cross-linking approach combined with subsequent affinity purification of the ligand covalently bound to its receptor allowed identification of its target., Key Results: The peptide bound with high affinity to a single class of binding sites, specifically localized in the striatum and substantia nigra of brains from guinea pigs and rats. When injected within the striatum of rats, the peptide stimulated in vitro and in vivo dopamine release and induced dopamine-like motor effects. We purified the target of the peptide, a ~151 kDa protein that was identified by MS/MS as angiotensin converting enzyme (ACE I). Therefore, we decided to name the peptide acein., Conclusion and Implications: The synthetic nonapeptide acein interacted with high affinity with brain membrane-bound ACE. This interaction occurs at a different site from the active site involved in the well-known peptidase activity, without modifying the peptidase activity. Acein, in vitro and in vivo, significantly increased stimulated release of dopamine from the brain. These results suggest a more important role for brain ACE than initially suspected., (© 2016 The British Pharmacological Society.)

α-Tocopherol (α-TOH), a dietary component of vitamin E, is well known for its antioxidant capacity. Nevertheless, recent studies have pointed out non-anti-radical properties including cellular and genomic actions. Decreased levels of α-tocopherol in the brain are associated with neuronal dysfunctions ranging from mood disorders to neurodegeneration. All these behavioral effects of α-tocopherol deficiency probably do not rely simply on its anti-radical properties, but could also be reminiscent of a not-yet characterized neuromodulatory action. We have thus measured the direct actions of α-tocopherol and of its natural phosphate derivative, α-tocopheryl phosphate (α-TP), on synaptic transmission in rodent hippocampus. These compounds had opposite actions on both glutamatergic and GABAergic transmission: whereas α-TOH potentiated these transmissions, α-TP inhibited them. Interestingly, these effects were both mediated by cannabinoid receptors (CB1Rs), because they were blocked by the CB1R antagonist AM251. Although α-tocopherol and α-tocopheryl phosphate did not directly bind CB1R, both α-TP and CB1R agonists inhibited forskolin-evoked Erk1/2 phosphorylation in a nonadditive manner. Furthermore, both α-tocopherol and α-tocopheryl phosphate attenuated depolarization-induced suppression of excitation and CB1R agonist-mediated hypothermia. Therefore, we identify α-tocopherol as new lipid modulator of the cannabinoid system in the rodent hippocampus, i.e., a novel "non-anti-radical" action of vitamin E, which may have some preeminent impact in neuronal disorders associated with vitamin E deficiency., (Copyright © 2011 Elsevier Inc. All rights reserved.)

A series of 7 new human/rat Corticotropin Releasing Hormone (h/r-CRH) analogues were synthesized. The induced alterations include substitution of Phe at position 12 with D-Phe, Leu at positions 14 and 15 with Aib and Met at positions 21 and 38 with Cys(Et) and Cys(Pr). The analogues were tested regarding their binding affinity to the CRH-1 receptor and their activity which is represented by means of percentage of maximum response in comparison to the native molecule. The results indicated that the introduction of Aib, or Cys derivatives although altering the secondary structure of the molecule, did not hinder receptor recognition and binding.

It has previously been reported that the cholecystokinin analog JMV-180 behaves differently on the rat and the mouse cholecystokinin-A receptor (CCK-AR). In mice this analog acts as an agonist on low- and high-affinity sites of the CCK-AR, whereas in rats this compound acts as an agonist on high-affinity sites and as an antagonist on low-affinity sites. In an attempt to understand why the same compound behaves differently on these two CCK-A receptors, we cloned the cDNA encoding the mouse CCK-AR. We then investigated a cellular model able to mimic the effect that was observed in rats and mice. HeLa cells were transiently cotransfected with plasmids leading to expression of the rat or mouse CCK-AR in the presence of pFos-Luc as reporter plasmid; such a plasmid placed the regulatory part of the human c-Fos gene upstream from the firefly luciferase structural gene (Luc). We then observed that the two CCK-A receptors behaved differently, not only in the presence of compound JMV-180 but also in the presence of cholecystokinin or even in absence of ligand; the rat CCK-AR was 2 to 3 times more potent than the mouse CCK-AR in inducing the reporter protein, whatever the ligand studied. This result was confirmed using the same kind of experiment with the reporter plasmid p(TRE)(3)-tk-Luc. Using various mutated receptors, we investigated the role of the putative third intracellular loop. We concluded that both the primary structure of the receptor and the cellular context are in part responsible for the differential behavior of these CCK-A receptors.

Glicentin (GLIC), oxyntomodulin (OXM), and peptide YY (PYY) released in blood by ileocolonic L-cells after meals may inhibit pancreatic secretion. Whereas OXM interacts with glucagon and tGLP-1 receptors, OXM 19-37, a biologically active fragment, does not. The purpose of this study was to measure the effect of OXM, OXM 19-37, GLIC, tGLP-1, and PYY on pancreatic secretion stimulated by 2 deoxyglucose (2DG), electrical stimulation of the vagus nerves (VES), acetylcholine and cholecystokinin octapeptide (CCK8) in anesthetized rats. The effect of OXM was also studied in dispersed pancreatic acini. Plasma oxyntomodulin-like immunoreactivity (OLI) was measured by radioimmunoassay after the exogenous infusion of OXM and after an intraduodenal meal. OXM 19-37, infused at doses mimicking postprandial plasma levels of OLI, decreased pancreatic secretion stimulated by 2DG, VES, or CCK8. Similar effects were found with OXM and GLIC. OXM 19-37 did not change the pancreatic stimulation induced by acetylcholine in vivo, or CCK-induced amylase release in isolated acini. Vagotomy completely suppressed the inhibitory effect of OXM 19-37 on CCK8-stimulated pancreatic secretion. PYY inhibited the effect of 2DG, but not that of CCK8, whereas tGLP-1, even in pharmacologic doses, had no effect on stimulated pancreatic secretion. OXM, OXM 19-37, but not tGLP-1, inhibit pancreatic secretion at physiologic doses, through a vagal neural indirect mechanism, different from that used by PYY, and probably through a GLIC-related peptide-specific receptor.

Bombesin pseudo-peptide analogues containing a hydroxamide function on the C-terminal part of the molecule, e.g. H-D-Phe-Gln-Trp-Ala-Val-Gly-His-Leu-NHOBzl 1 and H-D-Phe-Gln-Trp-Ala-Val-Gly-His-Leu-NHOH 2 were synthesized. These compounds were tested for their ability to recognize the bombesin receptor on rat pancreatic acini and on 3T3 cells, to stimulate (i) amylase secretion from rat pancreatic acini and (ii) accumulation of tritiated thymidine in 3T3 cells. Compounds 1 and 2 were able to recognize bombesin receptors on both models with high affinity (Ki = 7 +/- 2 and 5.8 +/- 0.9 nM on rat pancreatic acini, and Ki = 4.1 +/- 1.2 and 7.7 +/- 1.9 nM on 3T3 cells, respectively). Interestingly, compound 1 behaved as a potent agonist in stimulating amylase secretion from rat pancreatic acini and is able to stimulate thymidine accumulation in 3T3 cells, while compound 2 was able to potently antagonize bombesin-stimulated amylase secretion (Ki = 22 +/- 5 nM) in rat pancreatic acini and had no proper effect on 3T3 cells; however, it was able to inhibit bombesin-stimulated thymidine accumulation in 3T3 cells with high potency (Ki = 1.6 +/- 0.6 nM).

The tripeptide pyro-Glu-His-Pro-NH2[thyrotropin-releasing hormone (TRH)] was isolated from the hypothalamus as a thyrotropin-releasing factor. It has a broad spectrum of central nervous system-mediated actions, including the stimulation of exocrine pancreatic secretion. TRH is also synthesized in the endocrine pancreas and found in the systemic circulation. Enzymatic degradation of TRH in vivo produces other bioactive peptides such as cyclo(His-Pro). Because of the short half-life of TRH and the stability of cyclo(His-Pro) in vivo, we postulated that at least part of the peripheral TRH effects on the exocrine pancreatic secretion may be attributed to cyclo(His-Pro), which has been shown to have other biological activities. This study determines in parallel the peripheral effects of TRH and cyclo(His-Pro) as well as the putative contribution of other TRH-related peptides on exocrine pancreatic secretion in rats. TRH and its metabolite cyclo(His-Pro) dose dependently inhibited 2-deoxy-D-glucose (2-DG)-stimulated pancreatic secretion. TRH and all the related peptides tested had no effect on the basal and cholecystokinin-stimulated amylase release from pancreatic acinar cells in vitro. These data indicate that cyclo(His-Pro) mimics the peripheral inhibitory effect of TRH on 2-DG-stimulated exocrine pancreatic secretion. This effect is not detected on isolated pancreatic acini. Our findings provide a new biological contribution for cyclo(His-Pro) with potential experimental and clinical applications.

The aim of this study was to analyze the role of cholecystokinin (CCK(B)) receptor in human lymphoblastic Jurkat T cells. We investigated the trophic effect resulting from activation of such a receptor by using the reporter gene strategy. For this purpose, we transiently transfected Jurkat T cells with the reporter plasmid p[(TRE)3-tk-Luc] and found that CCK-8 was able to dose-dependently induce luciferase expression related to activator protein-1 (AP-1) activation with a maximal response identical to that obtained with compounds known to activate AP-1 complex (quantitatively, the same level of induction was obtained with 1 nM 12-O-tetradecanoylphorbol-13-acetate, 100 microM diacylglycerol, or 4 nM epidermal growth factor). The involvement of the CCK(B) receptor in such a stimulation was demonstrated by the inhibiting effect of the selective CCK(B) receptor antagonist PD-135,158. This effect was confirmed in COS-7 cells transfected with the cDNA of CCK(B) receptor cloned from Jurkat T cells. To better understand the AP-1-dependent luciferase expression in Jurkat T cells, we tested two specific inhibitors of serine/threonine phosphatases-1 and -2A: okadaic acid and calyculin A. These compounds strongly increased the phorbol-12-myristate-13-acetate response, whereas we have not observed a contribution of phosphatase inhibitors on a CCK-8-induced luciferase activity. To confirm that CCK(B) receptors are involved in AP-1 response, we investigated the CCK-8 effect on interleukin-2 expression, a natural endogenous gene regulated by several factors, including AP-1. In Jurkat T cells activated by phorbol-12-myristate-13-acetate and phytohemagglutinin, CCK-8 induced IL-2 expression. This induction was abolished by PD-135,158. Our results indicate that CCK-8 exerts a trophic effect in Jurkat T cells through stimulation of CCK(B) receptors by modulation of expression of AP-1-regulated genes.

The sequence of a cholecystokinin (CCK) related peptide was modified to obtain analogues, which interact selectively either with CCK-B, or with delta-opioid receptors. Two kinds of peptides were designed, namely, the cyclic peptides of the H-Tyr-cyclo (D-Pen-Gly-Trp-L/D-3-transmercaptoproline)-Asp-Phe-NH2 sequence (compounds 1a and 1b, respectively), and the linear peptides of the H-Tyr-D-Val-Gly-Trp-L/D-3-trans-methylmercaptoproline-Asp-Phe- NH2 sequence (compounds 2a and 2b, respectively). The only difference between the chemical structures of the linear analogues compared to the cyclic ones is that one covalent bond has been eliminated and a sulfur atom is replaced by a methyl group. Molecular modeling showed that, among low-energy conformers of cyclic compounds 1, there are three-dimensional structures compatible to the model for delta-receptor-bound conformer, suggested earlier [G. V. Nikiforovich, V.J. Hruby, O. Prakash, and C.A. Gehrig (1991) Biopolymers, vol. 31, pp. 941-955]. Results of binding assays fully supported the rationale for the design of compounds 1 and 2. The cyclic analogue 1a has Ki values of 4.5 and > 5000 nM at delta- and mu-opioid receptors, respectively; and IC50 values of 1.6 and > 10,000 nM for CCK-A and CCK-B receptors, respectively. The results of this study demonstrate a possibility to redirect a peptide sequence that interacts with one type of receptors (CCK-B receptors) toward interaction with another type (delta-opioid receptors) belonging to a different physiological system. This redirection could be performed by changing the conformational properties of the peptide with very minimal changes in its chemical structure.

In the course of our study concerning gastrin and cholecystokinin (CCK) receptors, we have synthesized and characterized a new labeled gastrin ligand, 125I-BH-[Leu15]-gastrin-(5-17) [(3-[125I]iodo-4-hydroxyphenyl)-propionyl-[Leu15]-gastrin-(5-17)]. Binding of 125I-BH-[Leu15]-gastrin-(5-17) to isolated canine fundic mucosal cells was specific, saturable and of high affinity. 125I-BH-[Leu15]-gastrin- (5-17) and 125I-BH-CCK-8[(3-[125I]iodo-4-hydroxyphenyl)-propionyl-CCK-8] interact with isolated canine fundic mucosal cells with small differences in maximal binding capacities and affinities, 3800 +/- 900 binding sites/cell (Kd = 0.52 +/- 0.23 nM) and 6200 +/- 1100 binding sites/cell (Kd = 0.31 +/- 0.18 nM), respectively. The relative order of potencies for gastrin and CCK analogs in displacing 125I-BH-[Leu15]-gastrin-(5-17) binding correlated well with those obtained using 125I-BH-CCK-8. Selective CCK/gastrin antagonists L-364,718 (MK-329) and L-365,260 also inhibited 125I-BH-[Leu15]-gastrin-(5-17) binding. These results indicate that 125I-BH-[Leu15]-gastrin-(5-17) binds to gastrin receptors in isolated canine fundic mucosal cells. We have also characterized 125I-BH-[Leu15]-gastrin-(5-17) binding to the human Jurkat lymphoblastic cell line (Jurkat cells) known to express the CCK-B/gastrin receptor. Saturation experiments have shown that both 125I-BH-[Leu15]-gastrin-(5-17) and 125I-BH-CCK-8 interact with a single class of high-affinity binding sites in the Jurkat cell line.(ABSTRACT TRUNCATED AT 250 WORDS)

Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester (JMV180), an analog of the C-terminal octapeptide of cholecystokinin (CCK-8), shows interesting biological activities behaving as an agonist at the high-affinity CCK binding sites and as an antagonist at the low-affinity CCK binding sites in rat pancreatic acini. Although we did not observe any major hydrolysis of the ester bond of Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester in our in vitro studies, we were aware of a possible and rapid cleavage of this ester bond during in vivo studies. To improve the stability of Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester, we decided to synthesize analogs in which the ester bond would be replaced by a carba (CH2-CH2) linkage. We synthesized the 3-amino-7-phenylheptanoic acid (beta-homo-Aph) with the R configuration in order to mimic the Asp-2-phenylethyl ester moiety and the 3-amino-6-(phenyloxy)hexanoic acid (H-beta-homo-App-OH), an analog of H-beta-homo-Aph-OH in which a methylene group has been replaced by an oxygen. (R)-beta-Homo-Aph and (R)-H-beta-homo-App-OH were introduced in the CCK-8 sequence to produce Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-(R)-beta-homo-Aph-OH and Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-(R)-beta-homo-App-OH. Both compounds were able to recognize the CCK receptor on rat pancreatic acini (IC50 = 12 +/- 8 nM and 13 +/- 5 nM, respectively), on brain membranes (IC50 = 32 +/- 2 nM and 57 +/- 5 nM, respectively), and on Jurkat T cells (IC50 = 75 +/- 15 nM and 65 +/- 21 nM, respectively). Like Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester, both compounds produced maximal stimulation of amylase secretion (EC50 = 6 +/- 2 nM and 4 +/- 2 nM, respectively) with no decrease of the secretion at high concentration indicating that these compounds probably act as agonists at the high-affinity peripheral CCK-receptor and as antagonists at the low-affinity CCK-receptor. Replacing the tryptophan by a D-tryptophan in such analogs produced full CCK-receptor antagonists. All these analogs might be more suitable for in vivo studies than Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester.

We have recently demonstrated the presence of specific high-affinity cholecystokinin binding sites of the central type on the Human JURKAT T Lymphocyte Cell line. In this paper, changes in intracellular Ca2+ concentration ([Ca2+]i) in response to CCK (cholecystokinin) peptides were measured in the Human JURKAT T Lymphocyte Cell line by fura-2 fluorometry. CCK-8 (the C-terminal octapeptide of CCK), the potent CCK analog Boc-[Nle28,31]CCK-7, stimulated ([Ca2+]i) mobilization in a dose-dependent manner in cells preloaded with fura-2 AM with an EC50 of 2.4 +/- 1 nM and 8 +/- 2 nM, respectively. The selective CCKB receptor agonists, namely Boc-Trp-Nle-Asp-Phe-NH2 and the cyclic analog JMV320, [formula: see text], were also potent in stimulating mobilization of [Ca2+]i with an EC50 of 32 +/- 10 nM and 25 +/- 10 nM, respectively. Compound JMV180, Boc-Tyr(SO3H)-Nle-Trp-Nle-Asp-2-phenylethyl ester, did not stimulate [Ca2+]i but inhibited the mobilization of [Ca2+]i elicited by 10 nM CCK-8 in a dose-dependent manner with an IC50 of 10 +/- 2 nM. The selective non-peptide CCKB receptor antagonist L-365,260 was more potent than the selective CCKA receptor antagonist MK-329 in inhibiting the [Ca2+]i mobilization elicited by 10 nM CCK-8 with IC50 values of 20 +/- 8 nM and 400 +/- 100 nM, respectively. These data indicated that CCK-8 and potent CCK analogs induced [Ca2+]i mobilization in the Human JURKAT T cell line through the CCKB/gastrin receptor type.

We have previously demonstrated that extracellular ATP can give medullary thymocytes the calcium message required for the induction of their blastogenesis, without mobilization of intracellular calcium. We describe here the effects of extracellular nucleotides on membrane permeability to monovalent and divalent cations in mouse thymocytes. Among all nucleotides tested, under physiological conditions, only ATP and, to a lesser extent, 2-methylthio-ATP, adenosine 5'-O-(3-thio-triphosphate), and ADP were able to depolarize thymocyte plasma membranes and to induce Na+ and Ca2+ influxes into thymocytes; other nonhydrolysable ATP analogs were only effective in the absence of Mg2+. The ATP-induced effects were inhibited in a dose-dependent manner by Mg2+ and greatly potentiated in its absence, which suggests that the tetrabasic ATP4 is probably the active species and that a phosphotransferase activity is not involved in its effects. There ATP-mediated changes in ion fluxes result from an increase in nonspecific permeability of thymocyte membranes, probably by pore formation. These ion flux changes might be responsible for the mitogenic induction of phorbol 12-myristate 13-acetate treated medullary thymocytes. The potency order for the adenine derivatives to affect these fluxes (ATP greater than ADP much greater than AMP greater than adenosine) suggests the presence of ATP specific receptors (P2 purinergic receptors) on thymocyte plasma membranes.