Neurotoxic Effects of Anhydroecgonine Methyl Ester, a Crack Cocaine Pyrolysis Product, on Primary Hippocampal Astrocytes: Effects of CB1 and TRPV1 Receptor Antagonism

Anhydroecgonine methyl ester (AEME), a pyrolysis product generated during crack cocaine consumption, has recognized neurotoxic potential; however, its effects on astrocytes remain poorly characterized. Astrocytes are essential for central nervous system homeostasis and antioxidant defense. Therefore, this study investigated the effects of AEME on cellular metabolic activity, glial fibrillary acidic protein (GFAP) immunoreactivity, and intracellular glutathione (GSH) levels in primary cultures of rat hippocampal astrocytes. We also evaluated whether pharmacological antagonism of cannabinoid receptor type 1 (CB1) and transient receptor potential vanilloid type 1 (TRPV1), using rimonabant (1 μM) and capsazepine (30 μM), respectively, could modify these responses. Primary astrocyte cultures obtained from the hippocampi of neonatal rats (1-4 days old) were exposed to AEME (0.1 mM), alone or in combination with each antagonist, for 2 h and 30 min. All animal procedures were approved by the Animal Ethics Committee of the Federal University of Alfenas (UNIFAL-MG, protocol number 0024/2025). AEME significantly decreased cellular metabolic activity, compared with the control group (15.08 ± 0.72% vs. 97.15 ± 1.52%; p < 0.0001), increased GFAP immunoreactivity (43,887 ± 3,376 vs. 27,078 ± 1,966 μm²; p < 0.001), and decreased intracellular GSH levels (1.47 ± 0.20 vs. 3.37 ± 0.10 μg/mg protein; p < 0.05). Neither rimonabant nor capsazepine prevented the AEME-induced reduction in cellular metabolic activity or the increase in GFAP-immunoreactive area. In contrast, cotreatment with rimonabant or capsazepine resulted in higher GSH levels than those observed in the group exposed only to AEME. Taken together, these findings indicate that AEME exposure induces reduced cellular metabolic activity, increased GFAP immunoreactivity, and depletion of intracellular GSH levels in primary hippocampal astrocytes. Although CB1 and TRPV1 receptor antagonism did not prevent AEME-induced alterations in metabolic activity or GFAP immunoreactivity, it was associated with the restoration of GSH levels, suggesting a possible involvement of these receptors in the modulation of astroglial redox homeostasis.