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Biomedical subjects

K H Westermann

Publications and source records attributed to K H Westermann.

At least 37 records · Page 2Linked to original sources
PubMed1976

Effect of harmine and brain lesions on apomorphine induced motor activity.

Application of harmine (10 mg/kg IP) 30 min before apomorphine decreased the motoric effects of the latter. Following harmine an increase in 5-HT and a decrease in 5-HIAA in different brain regions have been found. Injection of 5,6-DHT into nucleus medianus raphe 7 days before the experiment caused a significant increase of the apomorphine effect. Harmine pretreatment reduced this escessive motility as well as additional lesion of the substantia nigra with 6-OH-DA. Lesion induced by 6-OH-DA alone was without significant effect on the hypermotility following apomorphine. Application of PCPA 3 days before testing elicited an increase of apomorphine-induced hypermotolity which could be abolished by preceding harmine application. The experiments demonstrate the inhibitory effect of the central serotoninergic system on the apomorphine syndrome as well as the serotoninergic-dopaminergic interaction in hypermotility.

5,6-Dihydroxytryptamine↗
PubMed1976

[Nigrostriatally induced motor reactions in the rat. I. Rotational behavior and posture asymetry after intracerebral injection of apomorphine and dopamine].

Using a rotameter described by Ungrstedt, the influence of pretreatment with 6-hydroxy-dopamine and transections of the Capsula interna on the asymmetry of the animal's poise and movement following systemic and intracerebral administration of dopamine and apomorphine was studied. After lesion of the nigrostriatal tract, i.p. administered apomorphine caused the animals to rotate towards the damaged side. After injection of apomorphine in the Nucleus caudatoputamen of healthy animals, initial rotations towards the injection side with subsequent opposite rotation were observed, whereas dopamine injected into the Nucleus caudatoputamen and the Substantia nigra initiated rotations in contralateral direction only. Pretreatment with haloperidole nullified the effect of apomorphine. The results have proved the effectiveness both in the Nucleus caudatoputamen and the Substantia nigra of drugs stimulating the dopamine receptors. With intact rats, the two sides of the nigrostriatal system are functionally asymmetric, which is reflected by the quantitative differences of responses following stimulation of dopamine-sensitive receptors and the individually different preference of one rotational direction. These individual behavioural patterns are modified by experimental influences.

Animals↗
PubMed1976

[Nigrostiatally induced motor reactions in the rat. II. Cholinergic effect on rotational behavior and posture asymetry].

The rotational behaviour released in rats by apomorphine (5 mg/kg i.p.) following nigrostriatal lesions with 6-hydroxydopamine can be inhibited both by oxotremorin (1 mg/kg i.p.) and by injections of carbachol (30 mug) in the Nucleus caudatoputamen or Substantia nigra of the intact side. The rotations released in healthy animals by intrastriatal injections of apomorphine or carbachol are in opposite directions. The bendings of the body towards the side of injection (posture asymmetry) also observed after apomorphine administration in the Substantia nigra are inhibited by intrastriatal injections of carbachol. The results indicate that a dopaminergic-cholinergic interplay in the Nucleus caudatus, corresponding to the control functions of this nuclear area, is involved in the animals movement and poise.

Apomorphine↗
PubMed1975

[Brain transections for the localization of tremorigenic brain regions in the rat].

In rats transections of the brain have been carried out to localize tremorigenic centres. Ablation of cortical and diencephalic brain areas caused moderate reduction of oxotremorine induced tremor. A makred decrease of tremor intensity has been observed after transections eliminating the tegmental parts of the formation reticularis. We found in caudal sites of transections a shift of the tremor frequency to lower values including changes of distribution as well as the appearance of spontaneous tremor. Both the intensity of oxotremorine induced tremor and the appearance of spontaneous tremor was found to depend on body temperature. Harmine-induced tremor was influenced in opposite direction by ablation of the rostral brain areas.

Animals↗
PubMed1975

[A method for the objective determination of tremors in the rat].

Two methods for determining tremors in the rat, acceleration pick-up and electromyogram, including electronic evaluation by impluse rate and frequency are described technically, and the results obtained with either method are compared. Both methods allow quantitative analysis of the drug induced (arecoline) tremor. Electromyographically, the tremor effect can be recorded already after lower doses compared with the electro-mechanical method. Besides, the EMG can be employed on immobilized animals.

Animals↗
PubMed1975

[Tremor following intracerebral carbachol injection. 1.Carbachol sensitivity of various brain structures].

Tremor produced by intracerebral injection of carbachol. I. Susceptibility of different brain areas to carbachol Microinjections of carbachol into the lateral ventricle of rats caused tremor depending on dose. Intensity and duration of motor effects after injection of carbachol (30 mug/3 mul bilateral) into different brain areas were found to depend on localization: strongest tremor was elicited by injections into the nucleus caudatoputamen and cortex cerebri, moderate tremor by administration into the substantia nigra reticularis, globus pallidus and thalamic brain regions. Target areas of mean sensitivity were demonstrated in more rostral and caudal parts of the formatio reticularis. The injection of carbachol into the nucleus ruber, nucleus linearis and substantia nigra compacta brought about lowest tremor values. Ablation of the site of injection from the remaining brain abolished tremor induced by carbachol contrary to the tremor induced by oxotremorine.

Animals↗
PubMed1975

[Cholinergic effect on the dopamine turnover in the rat corpus striatum].

The peripheral administration of oxotremorine caused a significant increase in dihydroxyphenylacetic acid (DOPAC) in the striatum of rats, dopamine (DA) level was unaffected. Injection of oxotremorine into the substantia nigra failed to change the content of dopamine and its acid metabolites homovanillic acid (HVA) and DOPAC in striatum. Injection of oxotremorine or carbachol into the substantia nigra or into the caudate nucleus did not significantly influence the DA-turnover. The partly inconsistent results are discussed in connection with literature data in regard to the existence of excitatory as well as inhibitory cholinergic systems, which are located differently and are involved in the regulation of DA-turnover.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1975

Serotonin content in the central nervous system of rats and cholinergic tremor.

Oxotremorine did not alter the level of 5-HT and 5-hydroxyindoleacetic acid in different brain regions. The content of 5-HT in the striatum was diminished by electrolytic lesions of the raphe system, by microinjection of the selective depletor 5,6-dihydroxytryptamine into the raphe system and inhibition of synthesis by pCPA or pCAM. The intensity of oxotremorine-induced tremor was reduced only in some experimental groups without clear-cut correlation to the decreased 5-HT levels. In pCPA-pretreated animals resoring of 5-HT concentration by intrastriatal microinjection of 5-HT and ip administration of 5-HT did not reestablish tremor intensity. There is no evidence that cholinergic tremor is triggered indirectly and depends upon an intact 5-HT system.

Animals↗