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Biomedical subjects

M Opitz

Publications and source records attributed to M Opitz.

At least 37 records · Page 2Linked to original sources
PubMed1987

Participation of angiotensin II in learning and memory. III. Interactions of angiotensin II with GABAergic drugs.

The experiments were carried out on male albino rats trained and tested for retention (24 hr later) in a shuttle-box. Angiotensin II (AT II) 0.10 micrograms intracerebroventricularly (i.c.v.), gamma-aminobutyric acid (GABA) 100 micrograms i.c.v., bicuculline 0.5 and 1.0 mg/kg intraperitoneally (i.p.), and picrotoxin 0.5 and 1.0 mg/kg i.p. administered independently or in combinations immediately after training. AT II was found to improve retention. GABA also facilitated retention. Combination of AT II + GABA potentiated the memory-improving effect of AT II. Bicuculline and picrotoxin at a dose of 0.5 mg/kg did not affect retention, while at a dose of 1.0 mg/kg they improved it. Combinations of AT II + bicuculline (0.5 mg/kg) and AT II + picrotoxin (0.5 mg/kg) abolished the retention-improving effect of AT II. Bicuculline (0.5 mg/kg) or picrotoxin (0.5 mg/kg) abolished the retention-facilitating effect of the combination of AT II + GABA as well as the potentiating action of GABA on the memory effect of AT II. These results suggest the participation of GABAergic transmission in the CNS in the mechanisms of the long-term memory-improving effect of AT II.

Angiotensin II↗
PubMed1987

Mechanisms of the angiotensin II effects on the exploratory behavior of rats in open field. I. Interaction of angiotensin II with saralasin and catecholaminergic drugs.

The effects of the octapeptide angiotensin II (AT II) and its possible interaction with catecholaminergic (mainly dopaminergic) neurotransmission on the exploratory behavior of male rats in open field were studied. AT II changed exploratory behavior in a nonlinear dose-effect manner. The stimulant effects of AT II were antagonized by the AT II receptor antagonist saralasin. The AT II effects were increased by the DAergic agonists apomorphine and nomifensine and were decreased by the DAergic antagonist haloperidol and by the inhibitor of catecholamine synthesis alpha-methyl-para-tyrosine. It is suggested that the effects of AT II on open field behavior are realized through specific AT II receptors and through interactions with catecholaminergic (mainly dopaminergic) neurotransmission in the brain.

Angiotensin II↗
PubMed1976

[Histotopochemical investigations on elastic membranes of blood vessels with special regard to diabetes mellitus. III. Lipids (author's transl)].

Lipids have been investigated in the light microscope with Scarlet-Blue and for the fluorescentmicroscopy with rhodamine B and sulforhodamine B. Both of these reactions gave weak results. After using nilblue-sulfate for the detecting of acid and neutral lipids the presence of acid lipids could be shown in the walls of the vessels of normoglycemic men and animals. In the asymptomatical diabetes the tinction of elastic membranes was more intensive. Both acid and neutral lipids are present in a higher concentration in this stadium of diabetes mellitus as well as in the manifest diabetes of man.

Animals↗
PubMed1976

[Histotopochemical investigations on elastic membranes of blood vessels with special regard of diabetes mellitus. iv. Heavy metals (author's transl)].

Both of the methods for the histochemical detection of heavy metals have given corresponding results. In normal animals and also in non-diabetic men was a visible strong fluorescence after application of 2-methyl-8-hydroxychinoline and a strong sulfide-silver-reaction. This results are also in animals with diabetes mellitus clear. In asymptomatical and clinical manifest diabetes mellitus is established in contrast a weak exhibition of the elastic membranes of vessels with both of the methods.

Animals↗
PubMed1975

[Histotopochemical investigations on elastic membranes of blood vessels with special regard to diabetes mellitus. I. Proteins (author's transl)].

Histochemical investigations on elastic membranes of vessels under normally and diabetic conditions have been accomplished. These studies were made on man (diabetic and non-diabetic subjects) and on rats with streptozotocin-diabetes. The results are comparable among one another. The amino acids histidine, tyrosine and tryptophan were not demonstrable. The detection of primary NH2-groups (ninhydrin-Schiff-method and o-diacetylbenzen-reaction) was positive however. The results of the reactions in healthy men and animals were more distinct than in diabetic human subjects and animals. In healthy children the intensities of the histochemically reactions were higher than in adults.

Adult↗
PubMed1975

[Histotopochemical investigations on elastic membranes of blood vessels with special regard to diabetes mellitus. II. Carbohydrates (author's transl)].

Investigations on carbonhydrates were carried out with special regard to acid mucopolysaccharides and glycogen. The fluorescence-microscopical proof of acid micropolysaccharides with acridinorange (pH=3,3) and by means of the pseudoisocyanin-reaction (proof of-SO3H-groups) gave positive results on elastic membranes of blood vessels. These results were correlating to the increase of the diabetes mellitus. Healthy Wistar-rats did not show metachromasia with toluidinblue in the walls of the blood vessels, whereas in streptozotocin-diabetes there was strong metachromasia shown by these structures. The stages of diabetes in man were also correlated to an increase of metachromasia. The PAS-reaction, the staining with Best's carmine and the reaction with alizarinblue S for the proof of glycogen were positive in all blood vessels investigated.

Animals↗