The alpha(2)-adrenoceptor agonist dexmedetomidine suppresses memory formation only at doses attenuating the perception of sensory input.
It was investigated whether continuous rate infusion of the alpha(2)-adrenoceptor agonist dexmedetomidine can suppress memory formation by mechanisms other than reducing perception of sensory input in a fear-conditioning paradigm. Different groups of rats infused with either saline or dexmedetomidine (2.0, 4.0 or 10.0microg/kg bolus, followed by 2.0, 4.0 or 10.0microg/kg/h continuous rate infusion respectively), were subjected to a somatosensory-evoked potential (SEP) fear-conditioning paradigm. This paradigm combined the pairing of an innoxious conditioned stimulus (CS) and a noxious unconditioned stimulus (US), of which the latter was used to generate the SEPs (training phase).The following day, the perception of the US during the training phase was assessed by presenting the CS only and subsequently scoring the resulting duration of freezing behaviour (testing phase). Freezing behaviour was reduced only in those groups which demonstrated reduced SEPs. Based on these findings, it is concluded that dexmedetomidine suppresses memory formation only at doses reducing central nervous system activity in response to sensory input.
van Oostrom
Hugo
H
Department of Clinical Sciences of Companion Animals, Division Anaesthesiology and Neurophysiology, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.154, NL-3584 CM Utrecht, The Netherlands. H.vanOostrom@uu.nl
Stienen
Peter J
PJ
Doornenbal
Arie
A
Hellebrekers
Ludo J
LJ
D058647:Adrenergic alpha-2 Receptor Agonists; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D005239:Fear; D007260:Infusion Pumps; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology*; D009068:Movement / Q000187:drug effects; D010465:Perception / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology
D058647:Adrenergic alpha-2 Receptor Agonists; D012965:Sodium Chloride; D020927:Dexmedetomidine