Biomedical subjects

J Nogaya

Publications and source records attributed to J Nogaya.

22 records · Page 2Linked to original sources

PubMed1993

Memory facilitation by posttraining exposure to halothane, enflurane, and isoflurane in ddN mice.

The effect of low and high concentrations of halothane, enflurane, and isoflurane on posttraining memory function was studied in male ddN mice. Mice were trained to escape an aversive electric foot shock as an unconditioned stimulus within 3 s after being exposed to light and a buzzer as a conditioned stimulus. Immediately after training (first session: 30 trials), the animals were exposed to halothane, enflurane, or isoflurane for 120 min and then were tested again on the avoidance task (second session: 30 trials) 22 h after cessation of exposure. The performance ratios, [B/A] (i.e., A is the score in the first session, and B the score in the second) were compared between the anesthetized groups and their respective control (nonanesthetized) groups. Mean performance ratios in the control groups ([B/A]c) ranged from 136.8% to 163.9% and those in the anesthetized groups ([B/A]a) ranged from 151.4% to 174.7%. [B/A] in each anesthetized group exceeded [B/A] in its corresponding control group. [B/A]a significantly exceeded [B/A]c by 13.1% in the 1.23 minimum alveolar concentration (MAC) enflurane group (P < 0.05) and by 12.4% in the 0.29 MAC isoflurane group (P < 0.05). These results suggest that posttraining exposure to volatile anesthetics facilitates memory.

Animals↗

PubMed1991

The effects of age and anesthetic solubility on anesthetic-induced opisthotonus in mice.

In our previous report which indicated volatile anesthetics-induced opisthotonus in mice, we hypothesized that opisthotonus might relate with the rapidity of anesthetic induction, i.e., the blood/gas partition coefficient of the agent. To confirm this, we determined the incidence of opisthotonus induced by four different halogenated ethers (2.0% sevoflurane, 1.3% isoflurane, 2.0% enflurane, and 0.5% methoxyflurane) and 1.0% halothane, a haloalkane, in male ddN mice. The effect of age on opisthotonus was also evaluated by using young (10 +/- 2 weeks), middle-aged (6 +/- 1 mouths), and elderly (12 +/- 1 months) groups of male ddN mice. In each age group, the incidence of opisthotonus occurred in the following order: sevoflurane > isoflurane > enflurane > methoxyflurane > halothane. This partly supports our hypothesis as far as halogenated ethers are concerned. Halothane rarely produced opisthotonus. In the sevoflurane, isoflurane, and methoxyflurane groups, incidence was lower in middle-aged than in young or elderly mice, while incidence increased with age in the enflurane group.

Journal Article↗

PubMed1991

Subanesthetic concentrations of volatile anesthetics may enhance acquired avoidance training in ddN mice.

The effects of halothane, enflurane, and isoflurane on avoidance training were assessed in male ddN mice. Animals were trained to escape an aversive unconditioned stimulus (electric foot shock) within 3 s after being exposed to a conditioned stimulus (light and buzzer). Immediately after training (first session), the animals were exposed to halothane, enflurane, or isoflurane for 120 min and were then tested again on the avoidance task (second session) 30 min after cessation of the exposure. The performance ratios [B/A] (i.e., A is the score in the first session, and B the score in the second) were compared between the anesthetic groups and their respective control groups. Performance ratios in the control animals ([B/A]c) did not reach 100% except for those corresponding to the 0.5 and 1.0 MAC (minimal alveolar anesthetic concentration) halothane groups. Four of the nine performance ratios in the anesthetic groups ([B/A]a) exceeded 1.0. [B/A]a exceeded [B/A]c by 18.7% in the 0.25 MAC halothane group (P less than 0.05), by 13.5% in the 0.31 MAC enflurane group (i.e., not significant), and by 17.3% in the 0.29 MAC isoflurane group (P less than 0.01). [B/A]a/[B/A]c decreased dose-dependently for each anesthetic group. These results suggest that low concentrations of halothane, enflurane, and isoflurane may enhance the performance of ddN mice in acquired avoidance training performed 30 min after anesthetic exposure.

Anesthesia, Inhalation↗

PubMedDate not supplied

Psychomotor performance during initial stage of exposure to halothane, enflurane, isoflurane and sevoflurane in mice.

1. The dose-response relationship during the pre-anaesthetic and pre-equilibrium state of four inhalation anaesthetics (halothane, enflurane, isoflurane and sevoflurane) on fixed-ratio schedule-controlled behaviour was studied in mice. 2. Animals exposed to halothane, enflurane and isoflurane showed a biphasic pattern (i.e. a significant incremental increase in psychomotor responses at low inspired concentrations (0.1-0.4%) and decrements at greater concentrations) in a dose-dependent manner. Mean peak responses (per cent of control) were 132.3 (P < 0.01 vs control), 124.0 (P < 0.05) and 116.7% (P < 0.05) at 0.1% halothane, 0.3% enflurane and 0.2% isoflurane, respectively. 3. Sevoflurane did not increase schedule-controlled behavioural responses at any concentration. 4. The effect of subanaesthetic concentrations of inhalation anaesthetics on psychomotor performance can be evaluated as changes in the response rate in schedule-controlled behaviour.

Anesthetics, Inhalation↗