scholarly journals INTERACTION BETWEEN OREXIN AND OPIOIDS SYSTEMS OF THE STRUCTURES OF PARAAMYGDALAR COMPLEX IN THE REINFORCING EFFECTS OF SPONTANEOUS AND ACTIVATED SELF-STIMULATION OF THE LATERAL HYPOTHALAMUS

2017 ◽  
Vol 19 (1) ◽  
pp. 37-45
Author(s):  
Petr D Shabanov ◽  
Andrei Andreevich Lebedev ◽  
Vitalii Ivanovich Morozov ◽  
Sergei Vladimirivich Azarenko

Male Wistar rats were implanted bipolar electrodes into the lateral hypothalamus to study self-stimulation reaction in the Skinner box and microcannulas into the right lateral ventricle and structutes of the paraamygdalar complex (bed nucleus of stria terminalis, central nucleus of amygdala or nucleus accumbens) to study central effects of orexin (5 µg in 5 µl i. v. for an injection) on the reinforcing properties of pharmacological drugs. Intraperitoneal administration of trimeperidine (3 mg/kg), a synthetic opioid, was shown to increase self-stimulation of the lateral hypothalamus in the Skinner box (number of pedal pressings for 10 min) by 51.8%, and sulpiride (5 mg/kg, a small dose), an antagonist of D2 dopamine receptors, did not change but in the large dose (20 mg/kg) decreased self-stimulation by 49.3% (a number of pedal pressings, or self-stimulation frequency within 10 min). At the same time, SB-408124, an antagonist of OX1R receptors and its combination with orexin did not change self-stimulation indexes after intrastructural administration into the bed nucleus of stria terminalis, central nucleus of amygdala or nucleus accumbens. On the background of blockade of OX1R receptors by SB-408124 (1 µg for all structures) trimeperidine reduced their activating action on self-stimulation reaction. Sulpiride (5 mg/kg i. p., a dose not affecting self-stimulation reaction) blocked activating action of trimeperidine after blockade OX1R receptors by SB-408124 (1 µg). The data obtained can suggest that OX1R receptors participate in the reinforcing effects of synthetic opioid trimeperidine and the blockade of them by SB-408124 potentiate antagonist effects of sulpiride on self-stimulation (4 tables, bibliography: 23 refs).

2020 ◽  
Vol 18 (2) ◽  
pp. 123-130
Author(s):  
Eugenii R. Bychkov ◽  
Andrei A. Lebedev ◽  
Nikolai S. Efimov ◽  
Artyem S. Kryukov ◽  
Inessa V. Karpova ◽  
...  

The aim was to study the effect of rewarding and aversive stimulation of lateral hypothalamus on the turnover of monoamines in the terminal structures of the mesocorticolimbic and nigrostriatal systems: the nucleus accumbens (NAc) and striatum (St). The Wistar male rats were implanted electrodes in the lateral hypothalamus and further trained in self-stimulation test. Animals were also selected on aversive emotional reactions were observed after pressing the pedal for self-stimulation. Subsequently, forced stimulation was performed for 5 minutes and the animals were decapitated. The content of norepinephrine, dopamine (DA) and its metabolites 3,4-dioxiphenylacetic acid (DOPАС) and homovanilinic acid, serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in the nucleus accumbens and striatum were determined by high performance liquid chromatography with electrochemical detection. Positive and aversive stimulation of lateral hypothalamus decreased the level of DA in the NAc, however, only stimulation of the positive emotiogenic zone increased the DA and 5-HT turnover in the NAc, as evidenced by an increase in the DOPАС/DA and 5-HIAA/SER ratios, respectively. Rewarding and aversive stimulation decreased the level of 5-HT in St, however, only rewarding stimulation decreased the St level of 5-HIAA compared to control and animals with aversive stimulation. Rewarding stimulation increased the turnover of serotonin in St, as evidenced by the increase of 5-HIAA/5-HT ratios. The activity of the noradrenergic system did not change after rewarding and aversive stimulation. Thus, both rewarding and aversive electrical stimulation increases the turnover of DA and 5-HT in NAc and St. However, these changes are more significant after rewarding stimulation. DA turnover increases more in NAc, and 5-HT turnover in St. The data obtained indicate the specificity of the dopaminergic and serotonergic involvement for the formation of a modality of emotional reactions. Data may provide guidance for developing treatment strategies for neuropsychiatric diseases related to the malfunction of the reward system.


2015 ◽  
Vol 13 (2) ◽  
pp. 20-26
Author(s):  
Andrei Andreevich Lebedev ◽  
Eugeny Grigorievich Shumilov ◽  
Eugeny Rudolfovich Bychkov ◽  
Vitaly Ivanovich Morozov ◽  
Petr Dmitriyevich Shabanov

The orexin family of hypothalamic neuropeptides has been implicated in reinforcement mechanisms relevant to both food and drug reward. Previous behavioral studies with antagonists at the orexin A-selective receptor OX(1), have demonstrated its involvement in behavioral sensitization, conditioned place-preference, self-administration and reinstatement of drugs abuse. There are dense concentrations of hypocretin receptors, in brain regions implicated in drug reinforcement processes, such as the nucleus accumbens, ventral tegmental area and bed nucleus of the stria terminalis Adult male Wistar rats were implanted the stimulating electrodes to the lateral hypothalamus. Simultaneously, the microcanules were implanted into the BNST to inject the OX(1) receptor antagonist. Rats were trained to perform intracranial self-stimulation. The effects of the OX(1)-selective antagonist SB-408124 on brain stimulation-reward (BSR) were measured. SB-408124 injected into the BNST (1µg/1 µl in volume for each injection.) alone had no effect on self-stimulation of lateral hypothalamus. Amphetamine (1 mg/kg i.p.) potentiated BSR, measured as lowering of BSR threshold and enhancing of BSR frequency. Amphetamine-induced stimulatory effects on intracranial self-stimulation was blocked by injections of SB-408124 into BNST. These data demonstrate that OX(1) play an important role in regulating the reinforcing and reward-enhancing properties of amphetamine and suggest that orexin transmission is likely essential for establishing and maintaining the amphetamine habit in human addicts. However, the observations that OX1 antagonism reduce brain reward and block stress- and cue-induced reinstatement of drug-seeking suggests that this class of compounds may be useful additions to stress-reduction and other behavioral therapies in the treatment of substance abuse disorders.


2018 ◽  
Author(s):  
Julie Corre ◽  
Ruud van Zessen ◽  
Michaël Loureiro ◽  
Tommaso Patriarchi ◽  
Lin Tian ◽  
...  

AbstractThe dopamine (DA) hypothesis posits the increase of mesolimbic dopamine levels as a defining commonality of addictive drugs, initially causing reinforcement, eventually leading to compulsive consumption. While much experimental evidence from psychostimulants supports this hypothesis, it has been challenged for opioid reinforcement. Here, we use genetically encoded DA and calcium indicators as well as cFos to reveal that heroin activates DA neurons located in the medial part of the VTA, preferentially projecting to the medial shell of the nucleus accumbens (NAc). Chemogenetic and optogenetic manipulations of VTA DA or GABA neurons establish a causal link to heroin reinforcement. Inhibition of DA neurons blocked heroin self-administration, while heroin inhibited optogenetic self-stimulation of DA neurons. Likewise, heroin occluded the self-inhibition of VTA GABA neurons. Together, these experiments support a model of disinhibition of a subset of VTA DA neurons in opioid reinforcement.


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