PMID- 8864532
OWN - NLM
STAT- MEDLINE
DCOM- 19970106
LR  - 20190512
IS  - 0007-1188 (Print)
IS  - 0007-1188 (Linking)
VI  - 118
IP  - 8
DP  - 1996 Aug
TI  - Effects of intravenous anaesthetic agents on fast inhibitory oscillations in the 
      rat hippocampus in vitro.
PG  - 1977-86
AB  - 1. General anaesthetic agents prevent awareness of sensory input and subsequent 
      recall of sensory events after administration. The mechanisms involved in higher 
      sensory processing, including awareness and recall, are not fully elucidated. 
      However, fast oscillations in neuronal activity in the 20-80 Hz (gamma) range 
      have been strongly implicated. Here we have investigated the effects of two 
      anaesthetic agents and a sedative/hypnotic drug on these oscillations. 2. Trains 
      of fast oscillations, shown previously to be shaped by gamma-aminobutyric acid 
      (GABAA) receptor activation, were evoked by pressure ejection of L-glutamate (10 
      nM) onto the perisomatic region of hippocampal area CAI in the presence of 
      3-((R)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (R-CPP), 50 microM, 
      6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione (NBQX), 50 microM and 
      2-hydroxysaclofen, 0.2 mM. 3. Thiopentone (10-200 microM) and propofol (0.5-10 
      microM) dose-dependently decreased both the maximum oscillation frequency, by 
      approx. 90%, and the incidence of evoked rhythmic oscillations by approx. 60%. 
      Diazepam (0.05-1 microM) decreased maximum oscillation frequency by about 40% but 
      did not affect the incidence of evoked oscillations. 4. The similar effects of 
      thiopentone and propofol were mediated by both a large (about 600%) increase in 
      the decay constant (tau D) of GABAA receptor-mediated inhibitory postsynaptic 
      currents (i.p.s.cs) and a bicuculline-sensitive leak current. The two drugs had 
      differing effects on i.p.s.c. amplitude. Diazepam caused a small increase in tau 
      D (about 170%) and did not alter leak currents at the doses used. 5. Effects of 
      the anaesthetic agents were seen on the above measurements at similar 
      concentrations to those estimated in the CNS during clinical and veterinary 
      anaesthesia. We suggest that the effects on fast oscillations associated with 
      cognition may contribute to the mechanism by which these agents produce general 
      anaesthesia.
FAU - Whittington, M A
AU  - Whittington MA
AD  - Dept. of Physiology & Biophysics, Imperial College School of Medicine at St. 
      Mary's Hospital, London.
FAU - Jefferys, J G
AU  - Jefferys JG
FAU - Traub, R D
AU  - Traub RD
LA  - eng
GR  - Wellcome Trust/United Kingdom
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Br J Pharmacol
JT  - British journal of pharmacology
JID - 7502536
RN  - 0 (Anesthetics)
RN  - JI8Z5M7NA3 (Thiopental)
RN  - Q3JTX2Q7TU (Diazepam)
RN  - YI7VU623SF (Propofol)
SB  - IM
EIN - Br J Pharmacol 1996 Nov;119(6):1291
MH  - Anesthetics/*pharmacology
MH  - Animals
MH  - Diazepam/pharmacology
MH  - Dose-Response Relationship, Drug
MH  - Evoked Potentials/*drug effects
MH  - Hippocampus/*drug effects
MH  - In Vitro Techniques
MH  - Male
MH  - Propofol/pharmacology
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Thiopental/*pharmacology
PMC - PMC1909911
EDAT- 1996/08/01 00:00
MHDA- 1996/08/01 00:01
PMCR- 1997/08/01
CRDT- 1996/08/01 00:00
PHST- 1996/08/01 00:00 [pubmed]
PHST- 1996/08/01 00:01 [medline]
PHST- 1996/08/01 00:00 [entrez]
PHST- 1997/08/01 00:00 [pmc-release]
AID - 10.1111/j.1476-5381.1996.tb15633.x [doi]
PST - ppublish
SO  - Br J Pharmacol. 1996 Aug;118(8):1977-86. doi: 10.1111/j.1476-5381.1996.tb15633.x.