GHB: Difference between revisions
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==Pharmacology== | ==Pharmacology== | ||
GHB has at least two distinct binding sites<ref>Gammahydroxybutyrate: An endogenous regulator of energy metabolism | http://www.sciencedirect.com/science/article/pii/S0149763489800533</ref> in the central nervous system. GHB is an [[agonist]] at the newly characterized GHB receptor, which is excitatory,<ref>γ-Hydroxybutyric acid (GHB) and γ-aminobutyric acidB receptor (GABABR) binding sites are distinctive from one another: molecular evidence | http://www.sciencedirect.com/science/article/pii/S0028390804002527</ref><ref>A mechanism for γ-hydroxybutyrate (GHB) as a drug and a substance of abuse | http://www.medecinesciences.org/articles/medsci/abs/2005/03/medsci2005213p284/medsci2005213p284.html</ref> and it is a weak [[agonist]] at the [[GABA]]<sub>B</sub> receptor, which is inhibitory.<ref>A mechanism for γ-hydroxybutyrate (GHB) as a drug and a substance of abuse | http://www.medecinesciences.org/articles/medsci/abs/2005/03/medsci2005213p284/medsci2005213p284.html</ref> | GHB has at least two distinct binding sites<ref>Gammahydroxybutyrate: An endogenous regulator of energy metabolism (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/S0149763489800533</ref> in the central nervous system. GHB is an [[agonist]] at the newly characterized GHB receptor, which is excitatory,<ref>γ-Hydroxybutyric acid (GHB) and γ-aminobutyric acidB receptor (GABABR) binding sites are distinctive from one another: molecular evidence (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/S0028390804002527</ref><ref>A mechanism for γ-hydroxybutyrate (GHB) as a drug and a substance of abuse | http://www.medecinesciences.org/articles/medsci/abs/2005/03/medsci2005213p284/medsci2005213p284.html</ref> and it is a weak [[agonist]] at the [[GABA]]<sub>B</sub> receptor, which is inhibitory.<ref>A mechanism for γ-hydroxybutyrate (GHB) as a drug and a substance of abuse | http://www.medecinesciences.org/articles/medsci/abs/2005/03/medsci2005213p284/medsci2005213p284.html</ref> | ||
GHB induces the accumulation of either a derivative of [[tryptophan]] or [[tryptophan]] itself, possibly by increasing [[tryptophan]] transport across the blood–brain barrier. GHB-induced stimulation may be due to this increase in [[tryptophan]] transport to the brain and in its uptake by serotonergic cells. As the [[Serotonin|serotonergic]] system may be involved in the regulation of sleep, mood, and anxiety, the stimulation of this system by high doses of GHB may be involved in certain neuropharmacological events induced by GHB administration. | GHB induces the accumulation of either a derivative of [[tryptophan]] or [[tryptophan]] itself, possibly by increasing [[tryptophan]] transport across the blood–brain barrier. GHB-induced stimulation may be due to this increase in [[tryptophan]] transport to the brain and in its uptake by serotonergic cells. As the [[Serotonin|serotonergic]] system may be involved in the regulation of sleep, mood, and anxiety, the stimulation of this system by high doses of GHB may be involved in certain neuropharmacological events induced by GHB administration. | ||
However, at therapeutic doses, GHB reaches much higher concentrations in the brain and activates [[GABA]]<sub>B</sub> receptors, which are primarily responsible for its sedative effects.<ref>Drosophila GABAB receptors are involved in behavioral effects of γ-hydroxybutyric acid (GHB) | http://www.sciencedirect.com/science/article/pii/S0014299905007442</ref> GHB's sedative effects are blocked by GABA<sub>B</sub> [[antagonists]]. As the GABA system is the most prolific inhibitory receptor set within the brain, its modulation results in the [[sedating]] (or [[anxiety suppression|calming effects]]) of GHB on the nervous system. | However, at therapeutic doses, GHB reaches much higher concentrations in the brain and activates [[GABA]]<sub>B</sub> receptors, which are primarily responsible for its sedative effects.<ref>Drosophila GABAB receptors are involved in behavioral effects of γ-hydroxybutyric acid (GHB) (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/S0014299905007442</ref> GHB's sedative effects are blocked by GABA<sub>B</sub> [[antagonists]]. As the GABA system is the most prolific inhibitory receptor set within the brain, its modulation results in the [[sedating]] (or [[anxiety suppression|calming effects]]) of GHB on the nervous system. | ||
There has been somewhat limited research into the GHB receptor; however, there is evidence that activation of the GHB receptor in some brain areas results in the release of [[glutamate]], the principal excitatory neurotransmitter.<ref>Selective γ-hydroxybutyric acid receptor ligands increase extracellular glutamate in the hippocampus, but fail to activate G protein and to produce the sedative/hypnotic effect of γ-hydroxybutyric acid | http://onlinelibrary.wiley.com/doi/10.1046/j.1471-4159.2003.02037.x/abstract</ref> Drugs that selectively activate the GHB receptor cause absence seizures in high doses, as do GHB and [[GABA]]<sub>B</sub> agonists.<ref>Selective γ-hydroxybutyric acid receptor ligands increase extracellular glutamate in the hippocampus, but fail to activate G protein and to produce the sedative/hypnotic effect of γ-hydroxybutyric acid | http://onlinelibrary.wiley.com/doi/10.1046/j.1471-4159.2003.02037.x/abstract</ref> | There has been somewhat limited research into the GHB receptor; however, there is evidence that activation of the GHB receptor in some brain areas results in the release of [[glutamate]], the principal excitatory neurotransmitter.<ref>Selective γ-hydroxybutyric acid receptor ligands increase extracellular glutamate in the hippocampus, but fail to activate G protein and to produce the sedative/hypnotic effect of γ-hydroxybutyric acid | http://onlinelibrary.wiley.com/doi/10.1046/j.1471-4159.2003.02037.x/abstract</ref> Drugs that selectively activate the GHB receptor cause absence seizures in high doses, as do GHB and [[GABA]]<sub>B</sub> agonists.<ref>Selective γ-hydroxybutyric acid receptor ligands increase extracellular glutamate in the hippocampus, but fail to activate G protein and to produce the sedative/hypnotic effect of γ-hydroxybutyric acid | http://onlinelibrary.wiley.com/doi/10.1046/j.1471-4159.2003.02037.x/abstract</ref> | ||
Activation of both the GHB receptor and [[GABA]]<sub>B</sub> is responsible for the addictive profile of GHB. GHB's effect on [[dopamine]] release is biphasic.<ref>Drosophila [[GABA]]<sub>B</sub> receptors are involved in behavioral effects of γ-hydroxybutyric acid (GHB) | http://www.sciencedirect.com/science/article/pii/S0014299905007442</ref> This means that while low concentrations stimulate [[dopamine]] release via the GHB receptor,<ref>A specific gamma-hydroxybutyrate receptor ligand possesses both antagonistic and [[anticonvulsant]] properties (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/2173754</ref> higher concentrations inhibit [[dopamine]] release via [[GABA]]<sub>B</sub> receptors.<ref>Tonic GABA-ergic modulation of striatal dopamine release studied by in vivo microdialysis in the freely moving rat | http://www.sciencedirect.com/science/article/pii/001429999500369V</ref> After an initial phase of inhibition, [[dopamine]] release is then increased via the GHB receptor. | Activation of both the GHB receptor and [[GABA]]<sub>B</sub> is responsible for the addictive profile of GHB. GHB's effect on [[dopamine]] release is biphasic.<ref>Drosophila [[GABA]]<sub>B</sub> receptors are involved in behavioral effects of γ-hydroxybutyric acid (GHB) (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/S0014299905007442</ref> This means that while low concentrations stimulate [[dopamine]] release via the GHB receptor,<ref>A specific gamma-hydroxybutyrate receptor ligand possesses both antagonistic and [[anticonvulsant]] properties (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/2173754</ref> higher concentrations inhibit [[dopamine]] release via [[GABA]]<sub>B</sub> receptors.<ref>Tonic GABA-ergic modulation of striatal dopamine release studied by in vivo microdialysis in the freely moving rat (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/001429999500369V</ref> After an initial phase of inhibition, [[dopamine]] release is then increased via the GHB receptor. | ||
This explains the paradoxical mix of sedative and stimulatory properties of GHB as well as the so-called "rebound" effect experienced by individuals using GHB as a sleeping agent wherein they awake suddenly after several hours of GHB-induced deep sleep. Over time, the concentration of GHB in the system decreases below the threshold for significant [[GABA]]<sub>B</sub> receptor activation and activates predominantly the GHB receptor, leading to wakefulness. | This explains the paradoxical mix of sedative and stimulatory properties of GHB as well as the so-called "rebound" effect experienced by individuals using GHB as a sleeping agent wherein they awake suddenly after several hours of GHB-induced deep sleep. Over time, the concentration of GHB in the system decreases below the threshold for significant [[GABA]]<sub>B</sub> receptor activation and activates predominantly the GHB receptor, leading to wakefulness. | ||
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==Toxicity and harm potential== | ==Toxicity and harm potential== | ||
[[File:harmchart.png|thumb|right|300px|Radar plot showing relative physical harm, social harm, and dependence of GHB<ref>Development of a rational scale to assess the harm of drugs of potential misuse | http://www.sciencedirect.com/science/article/pii/S0140673607604644</ref>]] | [[File:harmchart.png|thumb|right|300px|Radar plot showing relative physical harm, social harm, and dependence of GHB<ref>Development of a rational scale to assess the harm of drugs of potential misuse (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/S0140673607604644</ref>]] | ||
GHB is [[toxicity::considered to be a safe and non-toxic substance when used responsibly]] or medically. The LD50 is above the active dosage, and there is no danger of acute toxicity. However, it can be dangerous when used as a recreational drug or abused. There have been many negative reports from recreational users who have overdosed, combined GHB with alcohol or other drugs, or accidentally dosed themselves unexpectedly.<ref>https://www.erowid.org/experiences/exp.php?ID=1926 | Erowid. "GHB Overdoses & Poisonings: An Experience with GHB (ID 1926)". Erowid.org. Jun 19, 2000. erowid.org/exp/1926 </ref> | GHB is [[toxicity::considered to be a safe and non-toxic substance when used responsibly]] or medically. The LD50 is above the active dosage, and there is no danger of acute toxicity. However, it can be dangerous when used as a recreational drug or abused. There have been many negative reports from recreational users who have overdosed, combined GHB with alcohol or other drugs, or accidentally dosed themselves unexpectedly.<ref>https://www.erowid.org/experiences/exp.php?ID=1926 | Erowid. "GHB Overdoses & Poisonings: An Experience with GHB (ID 1926)". Erowid.org. Jun 19, 2000. erowid.org/exp/1926 </ref> | ||
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It is strongly recommended that one use [[responsible drug use|harm reduction practices]] when using this drug. | It is strongly recommended that one use [[responsible drug use|harm reduction practices]] when using this drug. | ||
===Neurotoxicity=== | ===Neurotoxicity=== | ||
In multiple studies, GHB has been found to impair spatial memory, working memory, learning and memory in rats with chronic administration.<ref>Adolescent γ-hydroxybutyric acid exposure decreases cortical N-methyl-d-aspartate receptor and impairs spatial learning | http://www.sciencedirect.com/science/article/pii/S009130570400320X</ref><ref>Effects of subchronic administration of gammahydroxybutyrate (GHB) on spatial working memory in rats (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/17296081</ref><ref>γ-Hydroxybutyric Acid–Induced Cognitive Deficits in the Female Adolescent Rat | http://onlinelibrary.wiley.com/doi/10.1196/annals.1432.044/abstract</ref><ref>Neurotoxic effects induced by gammahydroxybutyric acid (GHB) in male rats | http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=6137924</ref> These effects are associated with decreased NMDA receptor expression in the cerebral cortex and possibly other areas as well.<ref>https://www.ncbi.nlm.nih.gov/pubmed/15582677 (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/15582677</ref> | In multiple studies, GHB has been found to impair spatial memory, working memory, learning and memory in rats with chronic administration.<ref>Adolescent γ-hydroxybutyric acid exposure decreases cortical N-methyl-d-aspartate receptor and impairs spatial learning (ScienceDirect) | http://www.sciencedirect.com/science/article/pii/S009130570400320X</ref><ref>Effects of subchronic administration of gammahydroxybutyrate (GHB) on spatial working memory in rats (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/17296081</ref><ref>γ-Hydroxybutyric Acid–Induced Cognitive Deficits in the Female Adolescent Rat | http://onlinelibrary.wiley.com/doi/10.1196/annals.1432.044/abstract</ref><ref>Neurotoxic effects induced by gammahydroxybutyric acid (GHB) in male rats | http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=6137924</ref> These effects are associated with decreased NMDA receptor expression in the cerebral cortex and possibly other areas as well.<ref>https://www.ncbi.nlm.nih.gov/pubmed/15582677 (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/15582677</ref> | ||
One study found that repeated administration of GHB to rats for 15 days drastically reduced the number of neurons and non-neuronal cells within the hippocampus and in the prefrontal cortex. With doses of 10 mg/kg of GHB, they were decreased by 61% in the hippocampus region and 32% in the prefrontal cortex, and with 100 mg/kg, they were decreased by 38% and 9%, respectively. This paper demonstrates contradicting effects on neuronal loss, with lower doses (10 mg/kg) producing the most neurotoxicity, and higher doses (100 mg/kg) producing less. | One study found that repeated administration of GHB to rats for 15 days drastically reduced the number of neurons and non-neuronal cells within the hippocampus and in the prefrontal cortex. With doses of 10 mg/kg of GHB, they were decreased by 61% in the hippocampus region and 32% in the prefrontal cortex, and with 100 mg/kg, they were decreased by 38% and 9%, respectively. This paper demonstrates contradicting effects on neuronal loss, with lower doses (10 mg/kg) producing the most neurotoxicity, and higher doses (100 mg/kg) producing less. |