Influence of ketamine on the spontaneous motility of chick embryos and its development.
The effects of acute and chronic application of ketamine on the resting spontaneous motility, its development and reactivity was studied in chick embryos of white Leghorns. 1. Acute application of ketamine (Narcamon) in a dose of 12.5 mg/kg e.w. partially depressed spontaneous motility as early as in 11-day old chick embryos. From day 15 of incubation ketamine very effectively blocked spontaneous motility. 2. Ketamine was fully ineffective in spinal preparations (decapitation on day 2 of incubation) of 11- and 13-day-old embryos. It was not until day 15 evoked that it depressed motility as in normal embryos. 3. Chronic continuous supply of ketamine (average dose 6.34 +/- 0.72 mg/kg e.w./24 h) from day 4 of incubation till day 8, 12, or 16 of incubation reduced the developmental decrease of spontaneous motility by 23.1-6.0% as compared to the controls. This effect was already observed after the first 4 days of chronic application of ketamine. 4. Chronic application of ketamine significantly diminished the strychnine activation and GABA-mediated depression of spontaneous motility. The depressive effect of the acute application of ketamine itself was hardly affected. The results have shown that ketamine interferes with the development of the endogenous rhythm of intrinsic activity and with the development of reactivity of the generator of embryonic spontaneous motility.
Sedlácek
J
J
Institute of Physiology, First Faculty of Medicine, Charles University, Prague.
D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D002642:Chick Embryo / Q000166:cytology* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005314:Embryonic and Fetal Development / Q000187:drug effects / Q000502:physiology*; D007649:Ketamine / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000494:pharmacology; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D005680:gamma-Aminobutyric Acid; D016202:N-Methylaspartate; D007649:Ketamine