Sequential Changes in Brain Glutamate and Adenosine A1 Receptors May Explain Severity of Adolescent Alcohol Withdrawal after Consumption of High Levels of Alcohol

Differential Effects of Intrahippocampal Administration of Ceftriaxone on Morphine Dependence and Withdrawal Syndrome in Rats

Glutamate is a key factor in opiate addiction. Glial glutamate transporter-1 (GLT-1) plays a prominent role in glutamate homeostasis. Therefore, different regimens of ceftriaxone as a GLT-1 activator were prescribed to determine whether modulating GLT-1 prevents morphine dependence or withdrawal syndrome. Rats received 10 mg/kg morphine subcutaneously for ten consecutive days. Intrahippocampal ceftriaxone (0.5 μL of 0.5 mM solution) was injected 30 min before morphine administration to assess its effect on dependence process. In the next experiment, after the animals became dependent, ceftriaxone was injected before or after the last morphine administration, and its effect on withdrawal symptoms was evaluated. The reversibility of developed dependence was evaluated in the conditions when morphine and ceftriaxone were administered simultaneously. Two hours after the last morphine injection, naloxone hydrochloride (1.5 mg/kg) was administered, and morphine withdrawal syndrome was recorded for 25 min. Ceftriaxone administration before each morphine injection caused a decrease in the occurrence of withdrawal symptoms. Single dose of ceftriaxone after or before the last dose of morphine did not change the withdrawal symptoms significantly. Ceftriaxone injection for 5 days after becoming dependent could decrease the occurrence of some withdrawal symptoms. Modulation of glutamate with ceftriaxone during morphine injection may be able to prevent dependence. However, a single dose of ceftriaxone after becoming dependent could not decrease withdrawal syndrome. More prolonged administration of ceftriaxone could alleviate the induced dependence.

Alcohol withdrawal and amphetamine co-use in an animal model for attention deficit hyperactivity disorder

Background: Non-medical use of amphetamine and other stimulants prescribed for treatment of attention deficit/hyperactivity disorder (ADHD) is of special concern when combined with alcohol consumption. In a previous study, we modeled chronic ethanol-amphetamine co-use in adolescent Long-Evans (LE) rats and provided evidence that amphetamine attenuates alcohol withdrawal symptoms.Objectives: This project modeled co-use of amphetamine with alcohol in adolescents with ADHD-like symptoms by examining ethanol-amphetamine administration in adolescent Spontaneously Hypertensive Rats (SHR), an experimental model for the study of ADHD. Withdrawal symptoms were compared among SHR and two control rat strains, LE and Wistar Kyoto (WKY).Methods: At postnatal day 32, parallel groups of 12-24 male SHR, WKY and LE rats were administered a liquid diet containing ethanol (3.6%) and/or amphetamine (20 mg/L). Following administration periods up to 26 days, rats were withdrawn from their treatment and tested for overall severity of alcohol withdrawal symptoms, general locomotor activity, and anxiety-like behavior.Results: Overall withdrawal severity was lower for SHR than for LE (p < .001) or WKY (p = .027). Co-consumption of amphetamine decreased withdrawal severity for LE (p = .033) and WKY (p = .011) but not SHR (p = .600). Only WKY showed increased anxiety-like behavior during withdrawal (p = .031), but not after amphetamine co-administration (p = .832).Conclusion: Alcohol withdrawal severity may be attenuated when co-used with amphetamine. However, as a model for ADHD, SHR adolescents appeared resistant to developing significant signs of alcohol withdrawal following alcohol consumption. Whether alcohol withdrawal symptoms are attenuated or absent, potential consequences could include a decreased awareness of an emerging problem with alcohol use.

Adult hemiconvulsive hemiatrophy syndrome: a novel clinicoradiologic disorder in adults

The association of focal motor seizures with cerebral hemiatrophy is a recognised rare paediatric syndrome known as 'hemiconvulsion, hemiatrophy and epilepsy' (HHE). To date, HHE has not been reported in adults. We present four adult patients with striking similarities to HHE, following alcohol withdrawal in chronic alcoholics. We document the imaging findings in the acute and subacute phases, discuss the underlying mechanisms and present a hypothesis regarding the pathophysiology.

The Role of the Adenosine System on Emotional and Cognitive Disturbances Induced by Ethanol Binge Drinking in the Immature Brain and the Beneficial Effects of Caffeine

Binge drinking intake is the most common pattern of ethanol consumption by adolescents, which elicits emotional disturbances, mainly anxiety and depressive symptoms, as well as cognitive alterations. Ethanol exposure may act on the adenosine neuromodulation system by increasing adenosine levels, consequently increasing the activation of adenosine receptors in the brain. The adenosine modulation system is involved in the control of mood and memory behavior. However, there is a gap in the knowledge about the exact mechanisms related to ethanol exposure’s hazardous effects on the immature brain (i.e., during adolescence) and the role of the adenosine system thereupon. The present review attempts to provide a comprehensive picture of the role of the adenosinergic system on emotional and cognitive disturbances induced by ethanol during adolescence, exploring the potential benefits of caffeine administration in view of its action as a non-selective antagonist of adenosine receptors.

Stimulants and Depressor Drugs in the Sleep-Wake Cycle Modulation: The case of alcohol and cannabinoids

A complex neurobiological network drives the sleep-wake cycle. In addition, external stimuli, including stimulants or depressor drugs, also influence the control of sleep. Here we review the recent advances that contribute to the comprehensive understanding of the actions of stimulants and depressor compounds, such as alcohol and cannabis, in sleep regulation. The objective of this review is to highlight the neurobiological mechanism engaged by alcohol and cannabis in sleep control.

Adenosine A2AReceptors in Substance Use Disorders: A Focus on Cocaine

Several psychoactive drugs can evoke substance use disorders (SUD) in humans and animals, and these include psychostimulants, opioids, cannabinoids (CB), nicotine, and alcohol. The etiology, mechanistic processes, and the therapeutic options to deal with SUD are not well understood. The common feature of all abused drugs is that they increase dopamine (DA) neurotransmission within the mesocorticolimbic circuitry of the brain followed by the activation of DA receptors. D₂ receptors were proposed as important molecular targets for SUD. The findings showed that D₂ receptors formed heteromeric complexes with other GPCRs, which forced the addiction research area in new directions. In this review, we updated the view on the brain D₂ receptor complexes with adenosine (A)2A receptors (A_2AR) and discussed the role of A_2AR in different aspects of addiction phenotypes in laboratory animal procedures that permit the highly complex syndrome of human drug addiction. We presented the current knowledge on the neurochemical in vivo and ex vivo mechanisms related to cocaine use disorder (CUD) and discussed future research directions for A_2AR heteromeric complexes in SUD.

Regulation of Synaptic Development by Astrocyte Signaling Factors and Their Emerging Roles in Substance Abuse

Astrocytes have critical functions throughout the central nervous system (CNS) and have emerged as regulators of synaptic development and function. With their highly complex morphologies, they are able to interact with thousands of synapses via peripheral astrocytic processes (PAPs), ensheathing neuronal axons and dendrites to form the tripartite synapse. In this way, astrocytes engage in crosstalk with neurons to mediate a variety of CNS processes including the regulation of extracellular matrix protein signaling, formation and maintenance of the blood-brain barrier (BBB), axon growth and guidance, homeostasis of the synaptic microenvironment, synaptogenesis, and the promotion of synaptic diversity. In this review, we discuss several key astrocyte signaling factors (thrombospondins, netrins, apolipoproteins, neuregulins, bone morphogenetic proteins, and neuroligins) in the maintenance and regulation of synapse formation. We also explore how these astrocyte signaling factors are impacted by and contribute to substance abuse, particularly alcohol and cocaine use.