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Biomedical subjects

J Z Nowak

Publications and source records attributed to J Z Nowak.

At least 109 records · Page 6Linked to original sources
PubMed1982

Impromidine-induced hypothermia in rats: effect of cimetidine and mianserine.

Impromidine, a highly potent histamine H2-receptor agonist, given i.v. at doses of 3.1-62 nmole, induced a dose-dependent hypothermia in the rat with a maximal effect after 15 min. Cimetidine, an H2-receptor antagonist, having no effect when administered alone, antagonized the hypothermic action of impromidine. Two antiserotoninergic agents, p-chlorophenylalanine and metergoline, and chronic treatment with an antidepressant mianserine reduced the impromidine-induced hypothermia. It is suggested that the impromidine-induced hypothermia is an H2-receptor-mediated phenomenon, and the antagonizing effect of mianserine is related to serotonin receptor blocking activity of the drug rather than to its direct H2-receptor antagonism.

Animals↗
PubMed1980

Interaction of histamine H2-receptor blocking drugs with the noradrenergic system in rat brain and heart.

The i.v.t. injection of burimamide (BUR), 50 micrograms, or cimetidine (CIM), 250 micrograms, decreased significantly the hypothalamic noradrenaline (NA) content by 32 and 21%, and significantly increased the whole brain 3-methoxy-4-hydroxyphenylglycol level by 46 and 28%, respectively. The i.p. administration of BUR or metiamide (MET), at a dose of 50 mg/kg, caused a decrease in the rat heart NA content by 34 and 21%, respectively; CIM had no effect at doses up to 100 mg/kg i.p., whether given acutely or chronically.

Animals↗
PubMed1980

Effects of the histamine H2-receptor agonists dimaprit and 4-methylhistamine on the central noradrenaline and serotonin system.

Effects of dimaprit and 4-methylhistamine, two histamine H2-receptor agonists, on noradrenaline and serotonin systems in the rat brain were investigated. Administration of dimaprit into the lateral brain ventricle produced 30% decrease in hypothalamal noradrenaline. 2 h after administration of dimaprit the level of 3-methoxy-4-hydroxyphenylglycol was increased by 50%. 4-Methylhistamine and histamine produced qualitatively the same effects as dimaprit. Dimaprit and 4-methylhistamine increased locomotor activity in tranylcypromine-treated rats. The hyperkinetic action of both drugs was prevented by phenoxybenzamine. Dimaprit had negligible effect on the serotonin system while 4-methylhistamine and histamine decreased serotonin and simultaneously increased 5-hydroxyindolcacetic acid. 4-Methylhistamine and histamine, but not dimaprit, evoked head-twitches in tranylcypromine-treated rats. It is concluded that dimaprit and 4-methylhistamine act similarly on the noradrenaline system, probably releasing noradrenaline, but having different effects on the serotonin system. 4-Methylhistamine (and histamine) probably releases serotonin from rat hypothalamus while dimaprit does not. The results are discussed in relation to a possible interaction of histamine with both noradrenaline and serotonin systems in the rat brain.

Animals↗
PubMed1980

Lack of influence of histamine H1-, and H2-receptor antagonists on histamine level in rat brain.

The intraperitoneal administration of three antihistaminic drugs of H1 type: mepyramine, diphenyhydramine (each 5 and 30 mg/kg) and danitracen (2 and 10 mg/kg) did not modify histamine level in the rat brain after 2 h. Histamine H2-receptor antagonists: cimetidine (25-250 microgram) and metiamide (100 microgram) given directly into the brain had no significant effect on histamine content after 1.5 h. L-histidine (0.5 g/kg i.p.) increased after 1.5 h histamine level in various experiments by 50-75% above control. All antihistaminic drugs did not change significantly histamine level in the brains of L-histidine-treated rats though a slight but consistent tendency to decrease the L-histidine effect in the group of H2-receptor blocking drugs was observed.

Animals↗
PubMed1980

Effect of histamine H1- and H2-receptor agonists on gamma-aminobutyric acid (GABA) content in hypothalamus and striatum of the rat brain.

The intraventricular administration of histamine in a dose of 500 microgram, and two histamine H2-receptor agonists i.e. 50-250 microgram of dimaprit and 100 microgram of 4-methylhistamine decreased GABA level after 30 min (by approximately 20%) in the hypothalamus, but not in the striatum of the rat brain. The level of GABA was significantly reduced by 100 microgram of dimaprit after 2 h. Drugs selectively stimulating histamine H1-receptor (100 microgram) did not significantly change GABA concentration of the rat hypothalamus. The results suggest the existence of an H2-receptor--mediated histamine--GABA interaction in the rat hypothalamus.

Animals↗
PubMed1980

Effect of amodiaquine on histamine level and histamine-methyltransferase activity in the rat brain.

Amodiaquine, 10(-5) M, totally inhibited the activity of histamine-methyltransferase (HMT) in the rat brain. Both peripheral (60 mg/kg i.p.) and central (50 and 100 microgram i.vt.) administration of the drug substantially reduced the HMT activity. Amodiaquine given i.p. or i.vt., in various doses, did not change the endogenous histamine (HI) level in the rat brain at any time studied (1-24 h). Amodiaquine (60 or 120 mg/kg i.p.) administered together with an inhibitor of diamine oxidase, i.e. aminoguanidine (either peripherally or centrally) had no effect on the endogenous HI content. Possible involvement of mechanisms other than methylation or oxidation in regulation of the endogenous HI level in the rat brain is discussed.

Amine Oxidase (Copper-Containing)↗
PubMed1980

Influence of oxotremorine on histamine level and histamine synthesis in the rat brain.

The i.p. administration of oxotremorine (2 mg/kg) produced a decrease of both formation of 14C-histamine and the activity of specific histamine-synthetizing enzyme--histidine decarboxylase (HD). Oxotremorine had no effect on histamine level in the brain when given alone, but lowered the amine content in L-histidine-treated rats. All of these effects of oxotremorine were antagonized by atropine sulphate, but not by atropine methyl nitrate--a cholinolytic drug which does not penetrate the blood-brain barrier. Presented findings indicate a possibility of ACh--HI interaction in the rat brain. Possible mechanism of oxotremorine action is discussed.

Acetylcholine↗
PubMed1979

Influence of histamine on the serotonergic system of rat brain.

Both histamine and 4-methylhistamine, after intraventricular injection into normal rats, reduced the levels of serotonin and increased those of 5-hydroxyindoleacetic acid in hypothalamus; after injection into tranylcypromine-treated rats, head twitches were induced which were blocked by antiserotonin agents. 2-Pyridylethylamine, an agonist of histamine H1 receptors, neither influenced serotonin level in hypothalamus nor evoked behavioural changes. It is concluded that injected histamine may release serotonin from the hypothalamus and that this produces the behavioural changes.

Animals↗
PubMed1978

An interaction of histamine H2-receptor antagonists with the noradrenergic system in rat brain.

Intraventricular administration of 50 microgram of burimamide or 250 microgram of either metiamide or cimetidine decreased the NA concentration in rat hypothalamus by nearly 30%. Cimetidine did not significantly influence either DA or DOPAC levels in striatum. Cimetidine and metiamide significantly potentiated locomotor activity of tranylcypromine-treated rats and this effect was antagonized by phentolamine. It is concluded that the three histamine H2-receptor antagonists released NA in rat brain.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1977

Direct or indirect action of histamine on dopamine metabolism in the rat striatum?

Intraventricular administration of 500 microgram of 2-pyridylethylamine, an agonist of the histamine (Hi) H1-receptor, produced a 20% increase of striatal HVA in the rat while the Hi H2-receptor agonist 4-methylhistamine had no influence on HVA and DOPAC levels. L-Histidine (1.5 g/kg) or amodiaquine (60 mg/kg) given i.p. increased HVA and DOPAC levels to the same extent as did pyridylethylamine. Histidine combined with tremorine had an additive effect with respect to the increase of DA acidic metabolites while mepyramine slightly attenuated the tremorine-induced rise of HVA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1977

Cholinergic link in the histamine-mediated increase in homovanillic acid in the rat striatum.

Administration of 500 microng of histamine into the lateral brain ventricle of the rat produced a 50% increase in striatal HVA. The DA level remained unchanged. The histamine-mediated elevation of HVA was abolished by pre-treatment with the antihistaminic drug - mepyramine. Moreover atropine significantly reduced the histamine-induced increase of HVA. It is concluded that histamine primarily activates cholinergic neurons and that the changes in DA metabolism are a consequence of an increased cholinergic activity.

Animals↗