Cortical αl-adrenergic regulation of acute and sensitized morphine locomotor effects

ArticleinNeuroreport 12(16):3483-3486 · November 2001with8 Reads
Abstract
The role of α1-adrenergic transmission was tested on locomotor effects of acute or repeated morphine (5 mg/kg, i.p.) administration. Prazosin, an α1-adrenergic antagonist, administered 30 min before morphine, either systemically (0.5 mg/kg, i.p.) or locally and bilaterally into the prefrontal cortex (200 pmol/side) reduced the stimulatory influence of morphine on locomotion. The progressive increase of the locomotor response induced by repeated morphine injections was blocked by a prazosin pretreatment but not the behavioral sensitization on the test day. These data suggest that blockade of cortical α1-adrenergic receptors reduces the expression of acute and sensitized locomotor responses to morphine, but does not prevent the induction of behavioral sensitization.
    • "Thus, increased DA transmission in the NAc mediates the rewarding/reinforcing effects of addictive drugs (Di Chiara and Imperato, 1988; Wise and Rompre, 1989; Pontieri et al., 1995; Koob et al., 1998; Robbins and Everitt, 1999; Ventura et al., 2003 Ventura et al., , 2005 Ventura et al., , 2007). However, recent evidence suggests major involvement of brain norepinephrine (NE) in the behavioral and central effects of rewarding pharmacological and natural stimuli (Darracq et al., 1998; Tassin, 1998; Drouin et al., 2001; Zarrindast et al., 2002; Ventura et al., 2007; Latagliata et al., 2010; Puglisi-Allegra and Ventura, 2012 ). Ventura et al. demonstrated that selective prefrontal NE depletion in mice abolished the increase of DA in the NAc induced by various classes of drugs of abuse and food (Ventura et al., 2003Ventura et al., , 2005Ventura et al., , 2007Ventura et al., , 2008 Latagliata et al., 2010). "
    [Show abstract] [Hide abstract] ABSTRACT: Aberrations in the elaboration of both aversive and rewarding stimuli characterize several psychopathologies including anxiety, depression and addiction. Several studies suggest that different neurotrasmitters, within the corticolimbic system, are critically involved in the processing of positive and negative stimuli. Individual differences in this system, depending on genotype, have been shown to act as a liability factor for different psychopathologies. Inbred mouse strains are commonly used in preclinical studies of normal and pathological behaviors. In particular, C57BL/6J (C57) and DBA/2J (DBA) strains have permitted to disclose the impact of different genetic backgrounds over the corticolimbic system functions. Here, we summarize the main findings collected over the years in our laboratory, showing how the genetic background plays a critical role in modulating amminergic and GABAergic neurotransmission in prefrontal-accumbal-amygdala system response to different rewarding and aversive experiences, as well as to stress response. Finally, we propose a top-down model for the response to rewarding and aversive stimuli in which amminergic transmission in prefrontal cortex (PFC) controls accumbal and amygdala neurotransmitter response.
    Full-text · Article · Feb 2015
    • "In order to induce tolerance to analgesic effect of morphine, mice were injected daily with morphine (5 mg/kg, sc). This dose has been found to cause profound analgesia without any side effects in mice (Drouin et al., 2001; Nayebi and Charkhpour, 2006). The responses to thermal stimuli 30 min after the morning dose were recorded daily by using hot plate test. "
    [Show abstract] [Hide abstract] ABSTRACT: Adjuvant drugs that can delay tolerance to morphine analgesia may lead to improved management of pain in chronic disease such as cancer. This study was aimed to investigate effect of buspirone, as a partial agonist of 5-HT1A receptor, on tolerance induced to morphine analgesic effect in animals with skin cancer. Study was carried on female Swiss albino mice. For skin tumorigensis, mice were treated with single dose of 7,12-dimethylbenz(a)anthracene (DMBA) and promoted by multiple dose of croton oil. Tolerance to morphine analgesia was induced by daily subcutaneous (sc) injection of morphine (5mg/kg for 30 days) and assayed by using the hot plate method. Results obtained from this study showed that pain threshold in mice with skin cancer were significantly lower. Tolerance to analgesic effect of morphine (5 mg/kg, sc) was appeared at day 15, whereas, in normal and skin tumor bearing mice co-treated daily with morphine (5 mg/kg, sc) and three different intraperitoneal (ip) doses of buspirone (5, 7.5 and 10 mg/kg) tolerance was observed at days 25 and 30. In conclusion our data indicate that concurrent use of morphine with buspirone may produce good cancer pain control and attenuate development of tolerance.
    Full-text · Article · Apr 2010
    • "In order to induce tolerance to the analgesic effect of morphine, mice were injected daily with morphine (5 mg/kg, sc). This dose has previously been shown to cause profound analgesia without any side effects in mice [8, 22] . The control group received daily injection of saline (1 ml/kg, sc) in the same manner. "
    [Show abstract] [Hide abstract] ABSTRACT: Adjuvant drugs that attenuate or inhibit the development of tolerance to morphine may lead to improved management of pain in chronic diseases such as cancer. The aim of this study was to investigate effect of fluoxetine, a specific 5-HT (5-hydroxytryptamine, serotonin) reuptake inhibitor, on tolerance induced to the analgesic effect of morphine in mice with skin cancer. The study was carried out on female Swiss albino mice. For skin tumorigensis, mice were initiated with a single dose of 7,12-dimethylbenz(a)anthracene (DMBA) and promoted by multiple doses of croton oil. Tolerance to morphine analgesia was induced by daily subcutaneous (sc) injections of morphine (5 mg/kg for 30 days) and assayed using the hot plate method. Results obtained from this study showed that pain thresholds in mice with skin cancer were significantly lower. Tolerance to the analgesic effect of morphine (5 mg/kg, sc) appeared at day 15, whereas in normal and skin tumor bearing mice co-treated daily with morphine (5 mg/kg, sc) and three different intraperitoneal (ip) doses of fluoxetine (0.16, 0.32 and 0.64 mg/kg) tolerance was observed at days 20, 25 and 30, respectively. In conclusion, our data indicate that concurrent use of morphine with fluoxetine may produce good cancer pain control and attenuate the development of tolerance.
    Full-text · Article · Jan 2010
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