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Biomedical subjects

A Szadowska

Publications and source records attributed to A Szadowska.

At least 55 records · Page 3Linked to original sources
PubMed1986

Changed sensitivity of alpha 2-adrenoceptors mediating a decrease in protein kinase inhibitor activity in the brain of vasopressin-hypertensive rats.

Clonidine produced an increase of cGMP content and a decrease of the endogenous type II inhibitor of protein kinase in rat hypothalamic slices. When administered to rats, the effect of clonidine on type II inhibitor activity in the hypothalamus and brain-stem depended on the dose. Low doses (10-50 micrograms X kg-1 i.p.) produced an increase, probably by stimulating presynaptic alpha 2-adrenoceptors, whereas large doses (200-1000 micrograms X kg-1 i.p.) produced a decrease of type II inhibitor activity by stimulating postsynaptic receptors. The development of vasopressin hypertension was associated with a gradual reduction of the response of the type II inhibitor to low and high doses of clonidine. In vasopressin-hypertensive rats neither small nor large doses of clonidine were able to induce changes in type II inhibitor activity suggesting subsensitivity of pre- and postsynaptic alpha 2-adrenoceptors. However, clonidine appeared to be equally effective in blocking electrically stimulated [3H]noradrenaline release from hypothalamic slices of vasopressin-hypertensive and control, normotensive rats. Reduced reactivity of postsynaptic alpha 2-adrenoceptors seems to be of great importance since treatment of vasopressin-hypertensive rats with 6-hydroxydopamine resulted in a decrease of blood pressure and reappearance of the sensitivity of postsynaptic alpha 2-adrenoceptors to clonidine.

Animals↗
PubMed1984

Effect of supersensitivity of pre- and postsynaptic dopamine receptors on the activity of endogenous inhibitor of cAMP dependent protein kinase in rat striatum.

Small presynaptically active doses of apomorphine (50-100 micrograms/kg) induced an increase, while large doses (1-10 mg/kg) provoked a decrease of type I inhibitor activity in rat striatum. Supersensitivity of postsynaptic D1 receptors was produced in rats by i.c.v. injection of 6-hydroxydopamine (6-OH-DA) and supersensitivity of presynaptic dopamine autoreceptors by i.p. administration of reserpine (1 mg/kg daily for 4 days). In reserpine pretreated rats apomorphine produced an increase in type I inhibitor activity after about 5 times lower doses than in control rats. This effect of apomorphine was blocked by aminophylline and by presynaptically active doses of haloperidol. In 6-OH-DA pretreated rats small doses of apomorphine did not change the type I inhibitor activity. The apomorphine induced decrease of type I inhibitor activity was seen after about 10 times lower doses of apomorphine than in control rats. This action of apomorphine was blocked by postsynaptically active doses of haloperidol and enhanced by aminophylline. The obtained results show that supersensitivity of presynaptic D2 dopamine autoreceptors and postsynaptic D1 receptors is accompanied by changes in the reactiveness of type I inhibitor activity to apomorphine.

Aminophylline↗
PubMed1983

Synthesis and action on the central nervous system of mescaline analogues containing piperazine or homopiperazine rings.

Structural juxtaposition of the 3,4,5-trimethoxyphenyl group in the same molecule with a piperazine or homopiperazine ring has been realized in a series of mescaline analogues (I-IV) as part of an investigation into the pharmacological properties of the seven-membered perhydro-1,4-diazepines (homopiperazines). The analogous six-membered piperazines were synthesized and tested as reference substances to determine whether the seven-membered ring conveyed special properties. A variety of pharmacological tests of action on the CNS showed that replacement of the amino group in mescaline by the heterocycles significantly alters the biological activity. In particular, both the piperazine and the homopiperazine derivatives displayed sedative activity to about the same extent.

Animals↗