Blockade of 5-HT2A Receptors May Mediate or Modulate Part of the Immobility Produced by Inhaled Anesthetics

Abstract

A subset of serotonin receptors, 5HT2A receptors, may mediate or modulate a minor portion of the immobility produced by inhaled anesthetics.

Evaluation of the Brain 5-HT2A Receptor Binding Index in Dogs with Anxiety Disorders, Measured with 123I-5I-R91150 and SPECT

“…However, the interval between sedation and scanning was less than 10 min, a time during which occurrence of these effects may be considered negligible, albeit not impossible. Different studies have also pointed out an effect of volatile anesthetics (e.g., isoflurane) on the serotonergic system (39,40). Mukaida et al described a decreased frontocortical release of the neurotransmitter serotonin in rats during isoflurane administration (39).…”

Imobilidade: uma ação essencial dos anestésicos inalatórios

“…Doherty et al 79 observed that R51703 antagonist decreases halothane MAC in dogs. Similarly, Zhang et al 75 found a maximum 60% decrease in isoflurane MAC in rats. These data are consistent with the hypothesis that 5-HT 2A receptors could directly mediate a minor component of inhalational anesthetics induced immobility.…”

“…Ao contrário, a somação temporal é eliminada pelo bloqueio NMDA 74 e anestesia com xenô-nio, indicando diferentes mecanismos de ação entre os anestésicos. Dados recentes mostraram que a inibição de canais de sódio pré-sinápticos pode bloquear a liberação de neurotransmissores, particularmente do glutamato 75 . Vários anestésicos voláteis inibem canais de sódio pré-sinápticos 76,77 , enquanto os não-imobilizantes não são capazes de fazê-lo 78 .…”

“…Conversely, temporal summation is eliminated by NMDA blockade 74 and anesthesia with xenon, indicating different mechanisms of action between anesthetic drugs. Recent data have shown that pre-synaptic sodium channels inhibition can block neurotransmitters release, especially glutamate 75 . Different volatile anesthetics inhibit pre-synaptic sodium channels 76,77 , while nonimmobilizers are unable to do it 78 .…”

Blockade of 5-HT2A and/or 5-HT2C receptors modulates sevoflurane-induced immobility

“…Moreover, when administered intrathecally and intravenously, ketanserin (given as a 5-HT 2A receptor antagonist) has been shown to decrease isoflurane MAC, the minimum alveolar concentration required to suppress movement in response to a noxious stimulus in 50% of human subjects [3]. However, several problems remain to be resolved concerning the possible role of the 5-HT 2A receptor in immobility induced by volatile anesthetics.…”