Bernard Francés

Biovector nanoparticles improve antinociceptive efficacy of nasal morphine.

AbstractPurpose. We have studied the antinociceptive activity and blood andbrain delivery of nasal morphine with or without Biovector™nanoparticles in mice. Methods. A tail flick assay was used to evaluate theantinociceptive activity. The kinetics of morphine were evaluated in blood andbrain, using tritiated morphine as tracer. Results. These nanoparticles were shown to increase the durationof the antinociceptive activity of morphine after nasal administration.This effect was not due to an increase of morphine in the blood; andthe analgesic activity of morphine in association with nanoparticleswas reversed by naloxone. The ED50 value was 33.6 ±15.6 mg/kg for morphine alone and 14.4 ± 7.6 mg/kg in presenceof nanoparticles. They were only effective at low doses (1.5 to 2.5 μg),a higher or a lower dose had no effect. No interaction was found betweennanoparticles and morphine. NaDOC, a permeation enhancer, was unable toimprove nasal morphine activity. Conclusions. These results show the presence of nanoparticles onlyat a very specific dose increases the antinociceptive activity of nasalmorphine in mice. The occurrence of a direct transport of morphinefrom the nasal mucosa to the brain is discussed.

Anti-opioid efficacy of neuropeptide FF in morphine-tolerant mice.

The modulatory effects of 1DMe (d-Tyr-Leu-(NMe)Phe-Gln-Pro-Gln-Arg-Phe-NH2), an agonist of Neuropeptide FF (NPFF) receptors, on opioid antinociceptive activity have been compared in naive and tolerant mice in the tail-flick and the hot-plate tests. In naive mice, 1DMe alone had no effect on pain threshold but decreased dose-dependently (3-22 nmol) the analgesic activity of morphine in both tests. In tolerant mice, injections of 60-fold lower doses of 1DMe (0.05-0.5 nmol) reverse morphine-induced analgesia in the tail-flick test but this anti-opioid effect was no longer observed with the highest doses of 1DMe tested (3-22 nmol). In the hot-plate test, the anti-opioid action of 1DMe was not detected, whatever doses tested. Neither the NPFF-like immunoreactivity content of spinal cord and of olfactory bulbs, nor the density of NPFF receptors in olfactory bulbs, were altered. These results indicate that a chronic morphine treatment modifies the pharmacological properties of NPFF but the type of pain test is crucial in determining NPFF effects.

Antisense oligonucleotides to human SQA-neuropeptide FF decrease morphine tolerance and dependence in mice

Neuropeptide FF (Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) is able to modulate opioid analgesia. Intracerebroventricular treatment for 5 days with antisense-oligodeoxynucleotides complementary to the sequence of human SQA-neuropeptide FF (Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) precursor gene or by mismatch-oligodeoxynucleotides did not change the antinociceptive activity of morphine in the mouse tail flick test. In contrast, antisense- but not mismatch-oligodeoxynucleotides attenuated significantly the tolerance to the analgesic activity of morphine and the withdrawal syndrome precipitated by naloxone in morphine-treated mice. These treatments with oligodeoxynucleotides did not modify neuropeptide FF-immunoreactivity content in whole brain but repeated injections of an agonist of neuropeptide FF receptors increased the intensity of morphine tolerance. These results demonstrate the important role of neuropeptide FF in opioid pharmacodependence.

An Alarm Pheromone Modulates Appetitive Olfactory Learning in the Honeybee (Apis Mellifera)

In honeybees, associative learning is embedded in a social context as bees possess a highly complex social organization in which communication among individuals is mediated by dance behavior informing about food sources, and by a high variety of pheromones that maintain the social links between individuals of a hive. Proboscis extension response conditioning is a case of appetitive learning, in which harnessed bees learn to associate odor stimuli with sucrose reward in the laboratory. Despite its recurrent use as a tool for uncovering the behavioral, cellular, and molecular bases underlying associative learning, the question of whether social signals (pheromones) affect appetitive learning has not been addressed in this experimental framework. This situation contrasts with reports underlining that foraging activity of bees is modulated by alarm pheromones released in the presence of a potential danger. Here, we show that appetitive learning is impaired by the sting alarm pheromone (SAP) which, when released by guards, recruits foragers to defend the hive. This effect is mimicked by the main component of SAP, isopentyl acetate, is dose-dependent and lasts up to 24 h. Learning impairment is specific to alarm signal exposure and is independent of the odorant used for conditioning. Our results suggest that learning impairment may be a response to the biological significance of SAP as an alarm signal, which would detract bees from responding to any appetitive stimuli in a situation in which such responses would be of secondary importance.

Opposing interplay between Neuropeptide FF and nitric oxide in antinociception and hypothermia

This study examined the ability of the anti-opioid Neuropeptide FF (NPFF) to modify the endogenous activity of nitric oxide (NO). Antinociceptive and hypothermic effects of 1DMe (D.Tyr-Leu-(n.Me)Phe-Gln-Pro-Gln-Arg-Phe-NH(2)), an NPFF agonist, and of L-NAME (N(omega)nitro-L-arginine methyl ester), an inhibitor of nitric oxide synthase, were investigated in mice. Intraperitoneal (i.p.) injection of L-NAME induced, in the hot plate test, a dose-dependent antinociception not reversed by naloxone, an opioid antagonist, but inhibited by L-Arg, the NO synthesis precursor. Intracerebroventricular (i.c.v.) injections of 1DMe inhibit the antinociceptive activity of L-NAME in a dose-dependent manner. On the contrary, L-NAME markedly potentiated hypothermia induced by 1DMe injected in the third ventricle. These data show that Neuropeptide FF receptors exert a dual effect on endogenous NO functions and could modulate pain transmission independently of opioids.

Cholera and pertussis toxins inhibit differently hypothermic and anti-opioid effects of neuropeptide FF

In mice pretreated intracerebroventricularly (i.c.v.) with pertussis or cholera toxins, effects of neuropeptide FF (NPFF), on hypothermia and morphine-induced analgesia, were assessed. NPFF and a potent NPFF agonist, 1DMe (0.005-22 nmol) injected into the lateral ventricle decreased morphine analgesia and produced naloxone (2.5 mg x kg(-1), s.c.)-resistant hypothermia after administration into the third ventricle. Cholera toxin (CTX 1 microg, i.c.v.) pretreatment (24 or 96 h before) inhibited the effect of 1DMe on body temperature, but failed to reverse its anti-opioid activity in the tail-flick test. CTX reduced hypothermia induced by a high dose of morphine (8 nmol, i.c.v.) but not the analgesic effect due to 3 nmol morphine. Pertussis toxin (PTX) pretreatment inhibited both morphine-hypothermia and -analgesia but did not modify hypothermia induced by 1DMe. The present results suggest that NPFF-induced hypothermia depends on the stimulation of Gs (but not Gi) proteins. In contrast, anti-opioid effects resulting from NPFF-receptor stimulation do not involve a cholera toxin-sensitive transducer protein.

Biochemical, cellular and pharmacological activities of a human neuropeptide FF-related peptide

We report on the biochemical, cellular and pharmacological activities of SQA-neuropeptide FF (Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2), a peptide sequence contained in the human neuropeptide FF (neuropeptide FF, Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) precursor. Quantitative autoradiography revealed that, in the superficial layers of the rat spinal cord, SQA-neuropeptide FF displayed the same high affinity for [125I]1DMe ([125I]D-Tyr-Leu-(NMe)Phe-Gln-Pro-Gln-Arg-Phe-NH2) binding sites (Ki = 0.33 nM) as did neuropeptide FF (Ki = 0.38 nM). In acutely dissociated mouse dorsal root ganglion neurones, SQA-neuropeptide FF reduced by 40% the depolarisation-induced rise in intracellular Ca2+ as measured with the Ca2+ indicator, Fluo-3. In mice, 1DMe and SQA-neuropeptide FF dose-dependently inhibited the antinociceptive effect of intracerebroventricular (i.c.v.) injections of morphine, but SQA-neuropeptide FF was less potent than 1DMe. Furthermore, SQA-neuropeptide FF, as well as 1DMe, produced marked hypothermia following third ventricle injections in mice. These data demonstrate that the human peptide, SQA-neuropeptide FF, exhibits biochemical and pharmacological properties similar to those of neuropeptide FF or neuropeptide FF analogues, and belongs to the neuropeptide FF family.

Apparent precoupling of κ- but not μ-opioid receptors with a G protein in the absence of agonist

Abstract Rabbit and guinea-pig cerebellum membranes contain a very high (> 80%) proportion of μ- and κ-opioid receptors, respectively. Rabbit (μ) and guinea-pig (κ) cerebellum membranes wre (i) labeled either with the opiate agonist. [ 3 H]etorphine (K d = 0.1–0.2 nM), or with the opiate antagonist. [ 3 diprenorphine (K d = 0.1 nM), in the absence or presence of Na + and/or 5′-guanylylimidodiphosphate (GppNHp), (ii) solubilized with digitonin (1%, w : v) and (iii) the radioactivity in the soluble extracts analyzed by ultracentrifugation in sucrose gradients. In the soluble extracts from rabbit cerebellum (μ) membranes, bound [ 3 H]etorphine sedimented faster (s 20 ≅ 12S) that bound [ 3 H]diprenorphine (10s), while is those from guinea-pig cerebellum (κ) membranes, bound [ 3 H]etorphine and bound [ 3 H]diprenorphine sedimented at the same position (12S). Na + selectively decreased recovery of the bound tritiated agonist in the two soluble preparations. When they had been generated in the presence of GppNHp but in the absence of Na + , the [ 3 etorphine complexes of the μ- and κ-opioid receptors as well as the [ 3 Hdiprenorphine complex of the κ-opioid receptor were all recovered at position 10S, indicating that GppNHp had induced a decrease of the apparent molecular size of the two types of opioid receptors. these data are interpreted in terms of μ- and κ-opioid receptors being capable of physically interacting with a G protein (GTP binding regulatory protein) yet, unlike the μ-opioid receptor which does so only in the presence of an agonist, the κ-opioid receptor appears to be precoupled with a G protein.

Roles of the ubiquitin proteasome system in the effects of drugs of abuse.

Because of its ability to regulate the abundance of selected proteins the ubiquitin proteasome system (UPS) plays an important role in neuronal and synaptic plasticity. As a result various stages of learning and memory depend on UPS activity. Drug addiction, another phenomenon that relies on neuroplasticity, shares molecular substrates with memory processes. However, the necessity of proteasome-dependent protein degradation for the development of addiction has been poorly studied. Here we first review evidences from the literature that drugs of abuse regulate the expression and activity of the UPS system in the brain. We then provide a list of proteins which have been shown to be targeted to the proteasome following drug treatment and could thus be involved in neuronal adaptations underlying behaviors associated with drug use and abuse. Finally we describe the few studies that addressed the need for UPS-dependent protein degradation in animal models of addiction-related behaviors.

Case Report of Cathinone-Like Designer Drug Intoxication Psychosis and Addiction With Serum Identification

The use of designer drugs commonly marketed as “Bath Salts” or “Energy” has dramatically risen in recent years. Fatalities and cases of aggressive behavior, even cannibalism have been recently reported in the media. However, these cases have been poorly documented. In this paper, we report a case of repetitive and similar acute psychotic episodes induced by Energy 3 intake. Comparative Analyses of Energy 3 sample and patient’s serum by gas chromatography-mass spectrometry detected the presence of 2 synthetic cathinone derivatives: methylenedioxypyrovalerone and pentylone. Finally, this patient’s clinical picture is characterized by the insidious development of dependence to this product. The absence of patient’s personal addiction history, the late onset of this dependence, and its high intensity, suggest a high addiction potential of these substances.