Influence of different anaesthetics on extracellular aminoacids in rat brain.
We used different anaesthetic procedures to study the possible effects of anaesthesia on extracellular aminoacid concentration in rat brain. Glutamate, aspartate and glycine concentrations were determined by HPLC in samples collected from the right fronto-parietal region of the rat brain cortex by transcerebral microdialysis before and up to 2 h following anaesthesia induction. Anaesthesia induced by ketamine, alone or in association with xylazine, caused a significant decrease in the levels of glutamate, aspartate and glycine, compared to before anaesthesia values (range: 27-72% according to the time of sampling and to the anaesthetic used). Inhalation anaesthesia with halothane (3%) in N2O/O2 mixture produced no significant effects on aminoacid levels. Equitensine (pentobarbital in association with chloral hydrate and ethanol) and pentobarbital also had no significant effect on glutamate, aspartate and glycine levels during anaesthesia. This demonstrates that some anaesthetics alter excitatory aminoacid release and suggests that Equitensine may represent an easy and reliable method to induce a long lasting anaesthesia associated without changes in excitatory aminoacid extracellular concentration.
Rozza
A
A
Department of Experimental and Applied Pharmacology, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy.
Masoero
E
E
Favalli
L
L
Lanza
E
E
Govoni
S
S
Rizzo
V
V
Montalbetti
L
L
D000596:Amino Acids / Q000187:drug effects* / Q000378:metabolism; D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000187:drug effects / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects*; D002545:Brain Ischemia / Q000378:metabolism / Q000503:physiopathology; D005110:Extracellular Space / Q000187:drug effects* / Q000378:metabolism; D018698:Glutamic Acid / Q000187:drug effects / Q000378:metabolism; D005998:Glycine / Q000187:drug effects / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009410:Nerve Degeneration / Q000188:drug therapy / Q000503:physiopathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D000596:Amino Acids; D000777:Anesthetics; D018696:Neuroprotective Agents; D018377:Neurotransmitter Agents; D001224:Aspartic Acid; D018698:Glutamic Acid; D005998:Glycine