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Biomedical subjects

E Hansson

Publications and source records attributed to E Hansson.

At least 91 records · Page 5Linked to original sources
PubMed1991

Mu and delta opiate receptors in neuronal and astroglial primary cultures from various regions of the brain--coupling with adenylate cyclase, localisation on the same neurones and association with dopamine (D1) receptor adenylate cyclase.

Primary cultures, enriched in neurones or astroglial cells, from three phylogenetically different regions of the brain of the rat, the cerebral cortex, the striatum and the brain stem, were used to investigate the presence of opiate receptors, coupled to adenylate cyclase. Morphine was used as a mu-receptor agonist and [D-Ala2, D-Leu5]-enkephalin (DADLE) was used as a delta-receptor agonist. In the neuronal cultures, both ligands inhibited the prostaglandin (PG)E1-stimulated intracellular accumulation of cyclic AMP dose-dependently, with the most prominent effects seen in the cultures of striatum and with DADLE being more potent than morphine. The opiate receptor antagonist, naloxone reversed the effects. Morphine and DADLE, added together, inhibited the PGE1-stimulated accumulation of cyclic AMP, less than the sum of the effects of each drug. Therefore, it might be that these opioid receptors are localized together on the same neurone. Striatal neurones contained dopamine receptors coupled to cyclic AMP, as second messenger. It was shown that the D1 (dopamine) receptor-stimulated activity of adenylate cyclase was inhibited by the mu and delta opioid receptor ligands. Thus, interactions at the level of adenylate cyclase seem to exist between D1, mu and delta opiate receptors. In the astroglial enriched cultures, DADLE inhibited the PGE1-induced accumulation of cyclic AMP, however, with a less prominent effect in the brain stem cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1991

Orchiectomy versus oestrogen in the treatment of advanced prostatic cancer.

The primary clinical efficacy of orchiectomy and the combination therapy of intramuscular polyoestradiol phosphate 80 mg monthly and oral ethinyl oestradiol 0.15 mg daily was evaluated by progression and cancer mortality rates in a series of 277 prostatic cancer patients representing part of the Finnprostate study. After a follow-up of 5 years there was a significant difference between the groups in terms of progression rate and prostatic cancer deaths. The oestrogen combination was more effective in delaying progression of the disease. The overall mortality rate was similar in both groups. About one-third of the patients were alive after 5 years.

Administration, Oral↗
PubMed1991

Intravesical chemotherapy (mitomycin C) versus immunotherapy (bacillus Calmette-Guérin) in superficial bladder cancer.

Both intravesical mitomycin C (MMC) and bacillus Calmette-Guérin (BCG; Pasteur strain F) were effective in the present prospective randomized multicenter study consisting of 91 patients with frequently recurrent superficial (Ta-T1) bladder cancer. The result was in favour of BCG, as shown by the measurements with complete response (CR), disease-free interval and recurrence rate. CR of 58% with MMC and 40% with BCG were reached in 22 instillation series on carcinoma in situ of 18 patients. Due to side effects, MMC instillations were discontinued in 8.6%, and BCG instillations in 19.6%, respectively. After the 2-year follow-up also 1 case of pulmonary tuberculosis occurred in the BCG group.

Administration, Intravesical↗
PubMed1991

Efficacy and side-effects of prazosin as a symptomatic treatment of benign prostatic obstruction.

This randomized double-blind crossover trial was conducted to assess the effects of prazosin, an alpha 1-adrenoceptor blocking drug, on the voiding of 35 patients with benign prostatic obstruction. Maximum and mean flow rates, residual urine, blood pressure and heart rate were measured at baseline and 2, 4, 6, and 8 weeks after starting the treatment with placebo or prazosin. At 4 weeks the treatments were switched over. The patients filled micturition charts at home and scored their voiding associated feelings. The maximum and mean flow rates increased significantly during prazosin treatment, as also did the maximum and mean voided volumes. Residual urine decreased and voiding improved subjectively but these changes were not statistically significant. Blood pressure was lowered and heart rate increased. Prazosin caused postural dizziness more often than placebo. Prazosin seems to offer an alternative to improve voiding in some patients with prostatic obstruction.

Aged↗
PubMed1990

Transport of valproate and its effects on GABA uptake in astroglial primary culture.

The antiepileptic drug Na(+)-valproate (VPA) is a broadspectrum anticonvulsant. It has been proposed to be involved in the inhibitory mechanisms of GABA-ergic systems. In this study, transport of the drug and possible influence on the GABA uptake were investigated in primary astroglial cell cultures from newborn rat cerebral cortex. The results show a Na+ and K+ independent high affinity uptake for VPA, with km and Vmax not significantly different from those observed for the GABA uptake. In the presence of the drug, the Km-value of the GABA uptake increased. The GABA uptake inhibitors guvacine, (RS)-Cis-4-OH-nipecotic acid and 4,5,6,7-tetrahydroisoxazolo (4,5- c) pyridin-3-ol (THPO) did not influence upon the uptake of VPA, suggesting a transport mechanism for the drug, separated from the GABA uptake carrier.

Animals↗
PubMed1990

Delta and kappa opiate receptors in primary astroglial cultures from rat cerebral cortex.

The effects of mu, delta, and kappa receptor-agonists on forskolin stimulated cyclic adenosine-3',5'-monophosphate (cAMP) formation were examined in astroglial enriched primary cultures from the cerebral cortex of newborn rats. Intracellular cAMP accumulation was quantified by radioimmunoassay. Morphine was used as a mu-receptor agonist, D-Ala-D-Leu-Enkephalin (DADLE) as a delta-receptor agonist and dynorphin 1-13 (Dyn) as a kappa-receptor agonist. Basal cAMP levels were unaffected by either the opiate agonists or the antagonists used. In the presence of the cAMP stimulator forskolin, morphine had no significant effect on the cytoplasmic cAMP levels. DADLE caused a dose related inhibition of the forskolin stimulated cAMP accumulation. The effects of this delta receptor stimulation was blocked with the selective antagonist ICI 174.864. In the presence of Dyn, the forskolin stimulated cAMP accumulation was inhibited in a dose related manner. This kappa receptor stimulation was blocked with the selective antagonist MR 2266. Co-administration of DADLE and Dyn resulted in a non additive inhibition of the forskolin stimulated accumulation of cAMP. These findings indicate that astroglial enriched cultures from the cerebral cortex of rats express delta and kappa-receptors co-localized on the same population of cells, and that these receptors are inhibitory coupled to adenylate cyclase.

Animals↗
PubMed1990

Interactions between cyclic AMP and inositol phosphate transduction systems in astrocytes in primary culture.

Astroglial cells in primary culture possess receptors with cyclic AMP and inositol phosphates (IP) as second messengers. The beta-receptor agonist, isoproterenol induces an increase in the accumulation of cyclic AMP, the alpha 2-receptor agonist clonidine inhibits the isoproterenol-induced accumulation of cyclic AMP, while the alpha 1-receptor agonist phenylephrine acts only on the inositol phosphate system. 5-Hydroxytryptamine (5-HT) stimulates, the formation of inositol phosphate, while isoproterenol and clonidine per se do not affect the inositol phosphate system. In the present paper the possibility of interactions between the cyclic AMP and the inositol phosphate transduction systems were investigated. In the presence of 10(-5) M 5-HT, in itself ineffective on the formation of cyclic AMP, isoproterenol stimulated the accumulation of cyclic AMP far more than in the absence of 5-HT. The potentiation was blocked by the 5-HT2 receptor antagonist ketanserin. On the other hand, there were no indications for a beta-receptor influence on the 5-HT-induced inositol phosphate formation. Stimulation of the alpha 2-receptor did not induce accumulation of inositol phosphate but significantly potentiated 5-HT2-receptor transduction, as measured by hydrolysis of phosphoinositide and formation of inositol phosphate. Stimulation by 5-HT also increased the formation of inositol phosphate after adrenergic stimulation and this effect was found to be synergistic at certain concentrations of adrenergic agonists. In addition, there was a statistically significant accumulation of cyclic AMP in the presence of both 5-HT and phenylephrine, none of which stimulated cyclic AMP alone. The results suggest specific interactions between the cyclic AMP and inositol phosphate systems on cultured astroglial cells.

Adenylyl Cyclases↗
PubMed1990

Opiate receptors in neuronal primary cultures.

The occurrence and characteristics of mu-, delta- and kappa-receptors were studied as effects of the respective agonists on forskolin-stimulated accumulation of cAMP in neuronal enriched primary cultures from the cerebral cortex of foetal rats. Morphine or [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAGO) were used as mu-receptor agonists. [D-Ala2,D-Leu5]-Enkephalin (DADLE) or [D-Pen2,D-Pen5]-enkephalin (DPDPE) were used as delta-receptor agonists and dynorphin 1-13 (Dyn) or U-50,488H were used as kappa-receptor agonists. In the presence of 10(-8)-10(-5) M morphine or 10(-8)-10(-5) M DAGO, there was a dose-related inhibition of the 10(-5) M forskolin-stimulated accumulation of cAMP. The inhibitory action of morphine or DAGO was reversed by naloxone. In the presence of 10(-9)-10(-6) M DADLE or 10(-9)-10(-6) M DPDPE, there was also a dose-related inhibition of the forskolin-stimulated accumulation of cAMP and a similar result was obtained in the presence of 10(-9)-10(-5) M Dyn or 10(-9)-10(-5) M U-50,488 H. These findings indicate that neurones from the cerebral cortex in culture express mu-, delta- and kappa-receptors, that inhibit the forskolin-stimulated accumulation of cAMP. Administration of 10(-5) M morphine and 10(-6) M DADLE or 10(-6) M DPDPE together, resulted in a non-additive inhibition of the forskolin-stimulated accumulation of cAMP, indicating the presence of both mu- and delta-receptors on the same population of cells.

Animals↗
PubMed1990

Stimulation of phospholipase D activity by phorbol esters in cultured astrocytes.

The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) was found to stimulate phospholipase D activity in cultured primary astrocytes. Both the hydrolysis and the transphosphatidylation reaction catalyzed by phospholipase D were studied in cells labeled with [3H]glycerol. Phosphatidic acid (PA) synthesis was increased after addition of 100 nM TPA. When ethanol was present in the cell culture medium, phosphatidylethanol (Peth), a product of phospholipase D-catalyzed transphosphatidylation, was formed. The half-maximum effective concentrations (EC50) of TPA were 25 nM for PA increase as well as for Peth formation. The formation of Peth in ethanol-treated cells was accompanied by an inhibition of the TPA-induced increase in labeled PA. Increasing ethanol concentrations led to an increase in [3H]Peth and a decrease in [3H]PA. A protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7), inhibited both the synthesis of PA and the formation of Peth observed after TPA addition to the astrocytes. Dioctanoyl-glycerol (100 microM) stimulated the formation of Peth in the presence of ethanol. In addition to the induction of Peth formation in astrocytes, TPA induced Peth formation in ethanol-treated neurons. The present results indicate that phospholipase D activity is stimulated by TPA in cultured primary brain cells. Modulation of phospholipase D activity by protein kinase C is a mechanism that may be important in signal transduction cascades.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Astrocytes in neurotransmission. A review.

The spatial position of astrocytes between neurons and the vascular endothelium might allow the astrocytic syncytium to act as a pathway for diffusion or active transport of substances between the environment of neurons and the cerebral blood vessels and ventricles. Furthermore, the intimate morphological arrangements between astrocytes and neurons might reflect biochemical cooperations between the cells. Astrocytes in the adult nervous system are in an unique position to regulate the environment of neurons and thereby their sensitivity. Some questions are raised: How do astrocytes receive neuronal signals? Are there local populations of astrocytes which respond specifically to small groups of neurons? Late results suggesting astrocytes to be a candidate for the supervision of neurotransmission are commented upon.

Animals↗
PubMed1989

Ethanol potentiates serotonin stimulated inositol lipid metabolism in primary astroglial cell cultures.

Serotonin-stimulated activation of phospholipase C in primary astroglial cell cultures was studied as a mean of evaluating the effect of acute ethanol exposition on this signal transduction system. The addition of 50-150 mM ethanol prior to stimulation with 10(-5) M serotonin led to a potentiation of the serotonin-induced [3H]-inositol phosphate formation and an increased incorporation of [3H]-inositol into the three phosphoinositides studied. This potentiating effect of ethanol was observed only when ethanol was added together with serotonin. No stimulatory effect of ethanol per se was found. Furthermore, ethanol had no effect on arginine-vasopressin, bradykinin or phenylephrine stimulated inositol lipid metabolism.

Animals↗
PubMed1989

Regulation of glutamine synthetase synthesis and activity by glucocorticoids and adrenoceptor activation in astroglial cells.

Glucocorticoids are known to induce the synthesis and activity of glutamine synthetase (GS; EC 6.3.1.2.) in astroglial cells. In the present paper, noradrenaline (NA), in itself ineffective upon GS regulation, potentiated GS activity in astroglial primary cultures in the presence of the glucocorticoid dexamethasone, the GS activity being further stimulated in the presence of glutamate (glu). Thus, adrenoceptor activation might interact with the glucocorticoid induced GS activity in astroglial primary cultures.

Animals↗
PubMed1989

Regulation of glutamate and GABA transport by adrenoceptors in primary astroglial cell cultures.

In astrocytes grown in primary cultures from cerebral cortex of neonatal rats, alpha 1-adrenoceptors regulate the active uptake of glutamate followed by an activation of glutamic oxaloacetate transaminase (GOT; EC 2.6.1.1.) and a slight activation of glutamine synthetase (GS; EC 6.3.1.2.) activity. The beta-adrenoceptors regulate the active uptake of GABA, and this is followed by an activation of gamma-aminobutyric acid alpha-ketoglutarate transaminase (GABA-T; EC 2.6.1.19.). The data suggest that astrocyte adrenoceptors may modulate neurotransmitter induced neuronal excitability.

4-Aminobutyrate Transaminase↗
PubMed1989

Effects of 2-guanidinoethane sulfonate on glutamate uptake in primary astroglial cultures from the rat cerebral cortex.

The competitive taurine uptake inhibitor 2-guanidinoethane sulfonate (GES) is frequently used to deplete cerebral pools of taurine. Previous work has revealed that extracellular glutamate increases during GES administration. In view of this, accumulation of glutamate in the absence or presence of 10 or 100 microM GES was measured in primary astroglial cultures from the rat cerebral cortex. At 100 microM, GES reduced Km as well as Vmax for glutamate uptake. A similar tendency was seen at 10 microM GES, but this was not statistically significant. The data suggest that GES is an uncompetitive inhibitor of reuptake of glutamate in astrocytes, which may underlie the previously noted GES-induced elevation of extracellular glutamate in vivo.

Animals↗
PubMed1989

Do persistent morphine effects involve interactions with the genome?

Male rats were administered morphine in a liquid diet until five days prior to mating with drug naive nulliparous female rats which received no treatment during gestation. The birth weight of resulting litters was significantly reduced. The preconceptionally morphine-treated offspring showed a 34.8% +/- 17.1% mortality during the first 8 days compared with 0% in the control group and their weight gain profile was decreased as compared with controls. A persistent effect of paternally administered morphine was seen in 90-day-old male offspring. A possible way to further enlighten the underlying mechanisms is proposed.

Animals↗
PubMed1989

Protein kinase C modulation of the ethanol effect on serotonin2 receptor transduction in astrocytes.

Acute ethanol exposure stimulated serotonin2 receptor signalling in cultured astrocytes. Pretreatment with the protein kinase C inhibitor H7 significantly increased the ethanol-induced potentiation of [3H]-inositol phosphates accumulation. The increase could be explained by an augmented activation of phospholipase C. The results indicate a role of PKC for the modulation of ethanol effects on cellular signalling.

Astrocytes↗
PubMed1989

Neurons in primary cultures from five defined rat brain regions--cellular composition and morphological appearance.

Primary cultures from 15-17 days old fetal rat cerebral cortex, striatum, hippocampus, substantia nigra and brain stem were grown for ten days. Cell aggregates were formed one to two days after seeding. The cell bodies migrated peripherally from the clusters during development and networks of processes were formed. The cultures from the different brain regions contained predominantly neurons, stained by an antiserum against the neuron-specific enolase (NSE). There were differences in morphological appearance of the aggregates and also of the single neuronal cells cultivated from the various brain regions. On the bottom of the culture dishes a monolayer was formed of predominantly undifferentiated (mesenchymal-like) cells. Some cells of the monolayer stained for the astrocyte markers glial fibrillary acidic protein (GFAp) or S-100. The majority of the cells were, however, unstained to these markers. Very few endothelial cells and macrophages were observed.

Animals↗