Low dose isoflurane exerts opposing effects on neuronal network excitability in neocortex and hippocampus.
The anesthetic excitement phase occurring during induction of anesthesia with volatile anesthetics is a well-known phenomenon in clinical practice. However, the physiological mechanisms underlying anesthetic-induced excitation are still unclear. Here we provide evidence from in vitro experiments performed on rat brain slices that the general anesthetic isoflurane at a concentration of about 0.1 mM can enhance neuronal network excitability in the hippocampus, while simultaneously reducing it in the neocortex. In contrast, isoflurane tissue concentrations above 0.3 mM expectedly caused a pronounced reduction in both brain regions. Neuronal network excitability was assessed by combining simultaneous multisite stimulation via a multielectrode array with recording intrinsic optical signals as a measure of neuronal population activity.
Department of Bioelectronics, FKE, Vienna University of Technology, Vienna, Austria. klaus.becker@meduniwien.ac.at
Klaus
K
Becker
Matthias
M
Eder
Andreas
A
Ranft
Ludwig
L
von Meyer
Walter
W
Zieglgänsberger
Eberhard
E
Kochs
Hans-Ulrich
HU
Dodt
D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D007530:Isoflurane / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D019579:Neocortex / Q000187:drug effects* / Q000502:physiology; D009415:Nerve Net / Q000187:drug effects* / Q000502:physiology; D061848:Optical Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley
D018685:Anesthetics, Inhalation; D007530:Isoflurane