Ketamine-Ethanol Combination Decreases Reduced Glutathione Levels and Activates both Intrinsic and Extrinsic Apoptotic Pathways Prior to Neuronal Death in SH-SY5Y Cells.
Felype Valentim Duarte Castelhano, Carolina Aparecida de Faria Almeida, Giulia de Assis Braz, Gabriela Otofuji Pereira, Rafaela Yolanda Silvino de Almeida, Matheus Lujan Pereira, Juliana Ligia Freires Ribeiro, Karin Argenti Simon, Rodrigo Portes Ureshino, Tânia Marcourakis, Larissa Helena Torres, Raphael Caio Tamborelli Garcia
Neurotoxicity Research June 7, 2025 DOI: 10.1007/s12640-025-00751-5 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | In vitro study Peer reviewed |
|---|---|
| Population | Human neuroblastoma SH-SY5Y cell line |
| Interventions | Ketamine Ethanol |
| Dose | 1 mM ketamine, 100 mM ethanol |
| Duration | 3, 6, 12, 24, and 48 hours of drug exposure |
| Topics | Ketamine Esketamine |
| Keywords | Ethanol Glutathione Neurotoxicity neurotoxic effects Neural damage Polysubstance use Nerve toxicity Drug synergy Cell death apoptosis Cellular death Programmed cell death Brain |
| Citations | 3 |
| Key points | Ketamine-ethanol combination induces neurotoxicity through oxidative stress and activation of both extrinsic and intrinsic apoptotic pathways, increasing the risk for neuronal damage compared to individual drug exposure. |
Abstract
Ketamine is an anesthetic drug that has been illegally used due to its hallucinogenic effects. Its use is often concomitant with drugs such as ethanol, which can cause irreversible damage to the central nervous system. This study investigates the neurotoxicity of ketamine-ethanol combination in human neuroblastoma SH-SY5Y cell line, exploring the mechanisms preceding cell death. Cell viability, oxidative stress parameters, and apoptosis pathways were assessed after 3 and 6 h of drug exposure. A concentration-response curve using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay determined the lowest observed adverse effect levels for ketamine (1 mM; K1) and ethanol (100 mM; E100). After 12, 24 and 48 h, MTT assay revealed a decrease in cell viability, with a possible synergistic effect in K1E100 at 48 h, confirmed by annexin-V/7-aminoactinomycin D flow cytometry analysis, which showed a higher proportion of late apoptotic cells. Mechanisms preceding cell death were assessed by measuring reduced glutathione (GSH) levels, glutathione-related enzymes activities, and apoptosis markers (caspase-8, Bax, Bcl-2, and caspase-3). GSH levels decreased after 6 h in E100 and K1E100. Glutathione peroxidase activity increased for all groups after 3 h and in K1 and K1E100 after 6 h. Glutathione reductase and glutathione S-transferase activities increased only for K1E100 after 3 h. K1E100 also showed increased caspase-8 and Bax expression after 3 and 6 h, respectively, indicating activation of both extrinsic and intrinsic apoptotic pathways. These results suggest that ketamine-ethanol combination induces neurotoxicity by triggering oxidative stress and apoptosis in a time-dependent manner prior to cell death, increasing the risk for neuronal damage compared to individual drug exposure. While these findings are promising, they should be interpreted with caution due to certain limitations, such as variability in enzyme activity measurements, reduced sample size for some markers, and the use of an immortalized, proliferative cell line. Further studies using differentiated neuronal cells are needed to validate and expand these observations.
Comparable studies
Other preclinical and animal studies on ketamine, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| mTOR-Dependent Synapse Formation Underlies the Rapid Antidepressant Effects of NMDA Antagonists Rats | 2010 | Observational study | |
| Activation of Glutamatergic Neurotransmission by Ketamine: A Novel Step in the Pathway from NMDA Receptor Blockade to Dopaminergic and Cognitive Disruptions Associated with the Prefrontal Cortex Conscious rats | 1997 | Dose-response study with microdialysis and behavioral testing | |
| NMDAR inhibition-independent antidepressant actions of ketamine metabolites Mice | 2016 | Preclinical study | |
| The dissociative anaesthetics, ketamine and phencyclidine, selectively reduce excitation of central mammalian neurones by N‐methyl‐aspartate Spinal neurons in decerebrate or pentobarbitone-anaesthetized cats and rats | 1983 | Experimental study | |
| R-ketamine: a rapid-onset and sustained antidepressant without psychotomimetic side effects Mice | 2015 | Experimental study |
Citations in the library
Cited by 2
- Editorial: Psychedelic substances and neurological diseases: from basics to clinical application Frontiers in Pharmacology March 16, 2026
- Dimethyltryptamine and harmine, components of ayahuasca, prevented cocaine-induced apoptosis in SH-SY5Y human neuroblastoma cells Archives of Toxicology November 12, 2025
Cites 3
- Ayahuasca, a psychedelic beverage, modulates neuroplasticity induced by ethanol in mice Behavioural Brain Research August 23, 2021
- Ketamine-induced neurotoxicity is mediated through endoplasmic reticulum stress in vitro in STHdhQ7/Q7 cells. Neurotoxicology July 2022
- The effects of sub-anesthetic ketamine plus ethanol on behaviors and apoptosis in the prefrontal cortex and hippocampus of adolescent rats. Pharmacology, Biochemistry, and Behavior July 23, 2019