HTR5A and cardiac arrest: Arecent study observed increased DMT levels in rat visual cortexfollowing cardiac arrest (Dean et al., 2019), afinding that supports the hypothesized role of endogenous DMT in NDEs(Strassman,2000; Timmermann et al., 2018).The specificity of this release needs to be considered, however, giventhat concentrations of 5-HT and other neurotransmitters are alsomassively increased during asphyxiation, cardiac arrest andhypercapnia and may compete with DMT at the 5-HT2AR (Johnson et al.,2005; Li et al., 2015; Nichols andNichols, 2019).