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2. Influence of ketamine on the spontaneous motility of chick embryos and its development
- Creator:
- Sedláček, J.
- Type:
- article, model:article, and TEXT
- Subject:
- chick embryo, embryonic motility, ketamine, strychnine, and GABA
- Language:
- English
- Description:
- The effects of acute and chronic application of ketamine on the resting spontaneous motility, its development and reactivity was studied in chick embiyos of white Leghorns. 1. Acute application of ketamine (NarcamonR) in a dose of 12.5 mg/kg e.w. partialy 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.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Interaction between glycine and glutamate in the development of spontaneous motility in chick embryos
- Creator:
- Sedláček, J.
- Type:
- article, model:article, and TEXT
- Subject:
- chick embryo, spontaneous motility, glycine, glutamate, and NMDA receptor
- Language:
- English
- Description:
- In this study we investigated whether also glycine fullfils the function as co-activator in glutamatergic activation of NMDA receptors in the neuronal apparatus of spontaneous motility in chick embryos.The successive application of glycine (5 or 10 mg/kg egg weight (e.w.) and glutamate (15 mg/kg e.w.) in a 10 min interval significantly increased the activation of spontaneous motility of 17-day-old chick embryos in comparison with the effect of glutamate alone. This effect did not depend on the order of application of the drugs. In 13-day-old embryos, glycine was ineffective in both doses. It is concluded from these results that the modulatory effect of glycine is evidently a later developmental acquisition (after day 15 of incubation) in the embryogenesis of NMDA-ergic activation of spontaneous motility in chick embryos similarly as glycinergic inhibition.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Interaction of beta-carboline with chick embryo spontaneous motility
- Creator:
- Sedláček, J., Hebebrand, J., and Reichelt, H.
- Type:
- article, model:article, and TEXT
- Subject:
- chick embryo, embryonic motility, β-carbolincs, CNS, and GABA receptor
- Language:
- English
- Description:
- The effect of bcta-carboline (Ji-CCE) on spontaneous motility and its development was studied in chick embryos between the 11th and 19th day of incubation. 1. Acutely administered p-CCE (7.5 mg/kg e.w.) already induced significant activation of motility in 11-day-old embryos. From the 17th day of incubation activation acquired a paroxysmal character. 2. In spinal embryos (decapitated on the second day of incubation) there was no such activating effect, demonstrating that it is associated with supraspinal components of the CNS. 3. In chronic administration from the fourth day of incubation (1.55 ± 0.24 mg/kg e.w./24 h), P-CCE led to reduced development of spontaneous motility. The effect was concentrated in the period between the fourth and eighth day of incubation. The chronic administration of P-CCE augmented the activating effect of metrazol and weakened GABA-inhibition of spontaneous motility. 4. On the basis of their findings, the authors express the hypothesis that the benzodiazepine /1-CCE-scnsitive component of the complex GABA receptor evidently already functions from the beginning of the second half of incubation of chick embryos.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Sensitivity of the generator of spontaneous motility in chick embryos to the acute and chronic administration of MPTP
- Creator:
- Sedláček, J.
- Type:
- article, model:article, and TEXT
- Subject:
- chick embryo, spontaneous motility, MPTP, nialamide, and MAO
- Language:
- English
- Description:
- The acute and chronic effect of l-methyl-4-plicnyl-l,2,3,6- tetrahydropyridine (MPTP) on spontaneous motor activity and its development was studied in chick embryos. 1. From the 13th day of incubation, the acute effect of MPTP (30 mg/kg e.w., up to 60 min after administration) consisted in significant depression of spontaneous motility. From the 17th day, the effect of MPTP in supraspinal compartments of the CNS also began to participate in this depression. 2. Flic subacute effect of MPTP (up to 24 h after a single dose) was lethal for 11-day-old embryos. Conversely, in older embryos resting motility partly recovered, with signs of an inverse correlation to the embryo’s age. The final effect, however, consisted in absolute failure of the hatching process. 3. The chronic effect of MPTP (3.57 mg/kg e.w./24 h, from the 4th to the 16th day of incubation) led to a developmental reduction of spontaneous motor activity, chiefly from the 8th to 12th day of incubation. 4. The interaction of nialamide (25 mg/kg e.w.), a blocker of monoaminooxidasc produced disparate results with the effect of MPTP in young and old embryos.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public