Cryoprotection of human bone marrow committed stem cells (CFU-c) by dextran,glycerol and dimethyl sulfoxide

Summary Dextran, glycerol and dimethyl sulfoxide (DMSO), alone or in combination, were used for cryoprotection of human bone marrow cells. The viability of cryopreserved cells was assessed by culture of myelopoiesis-committed stem cells (CFU-c) in vitro. A significantly better protection against freezing injury was obtained by 9% dextran in combination with 3 or 5% DMSO, and also with 5 or 10% DMSO alone, than with either 15% glycerol or 9% dextran with 1% DMSO.Acknowledgments. This work has been supported by the grant Nr. 140.AK-79 (5) from the Swiss Cancer League.     

Melatonin receptors limit dopamine reuptake by regulating dopamine transporter cell-surface exposure

Melatonin, a neuro-hormone released by the pineal gland, has multiple effects in the central nervous system including the regulation of dopamine (DA) levels, but how melatonin accomplishes this task is not clear. Here, we show that melatonin MT₁ and MT₂ receptors co-immunoprecipitate with the DA transporter (DAT) in mouse striatal synaptosomes. Increased DA re-uptake and decreased amphetamine-induced locomotor activity were observed in the striatum of mice with targeted deletion of MT₁ or MT₂ receptors. In vitro experiments confirmed the interactions and recapitulated the inhibitory effect of melatonin receptors on DA re-uptake. Melatonin receptors retained DAT in the endoplasmic reticulum in its immature non-glycosylated form. In conclusion, we reveal one of the first molecular complexes between G protein-coupled receptors (MT₁ and MT₂) and transporters (DAT) in which melatonin receptors regulate the availability of DAT at the plasma membrane, thus limiting the striatal DA re-uptake capacity in mice.     

Modulation of dopaminergic transmission by alpha-noradrenergic agonists and antagonists: Evidence for antidopaminergic properties of some alpha antagonists

Summary The effects on dopamine (DA) metabolism, on³H-spiperone binding and on amphetamine-induced stereotypies of a variety of drugs with different actions on alpha₁-and alpha₂-noradrenergic (NA) receptors have been investigated.The preferential alpha₂-antagonists yohimbine, rauwolscine, piperoxane and esproquin as well as the preferential alpha₁-antagonists corynanthine and WB4101 increased homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the rat striatum, mesolimbic area, and cortex. Prazosine and clonidine tended to reduce HVA and DOPAC. The preferential alpha₂-antagonists, tolazoline and RX-781094A, had no measurable effects on DA metabolism even at high doses.Those compounds which in comparable doses increased DA metabolism inhibited³H-spiperone binding in the hippocampus. The effects in the striatum and cortex were smaller and did not show a relation to those in hippocampus or on DA metabolism. Only the yohimbine alkaloids antagonized amphetamine-induced stereotypies.The results suggest that the effects on DA metabolism at least of yohimbine, rauwolscine, and corynanthine are related to their intrinsic antidopaminergic properties. The same might be true, although with a lesser degree of certainty, for piperoxane, esproquin, and WB4101.Since many of the tested compounds possessing alpha-antagonistic properties interacted with the DA system, a close molecular relationship between alpha-noradrenergic and DA receptors might be anticipated. The preference of these compounds for the hippocampal subtype of DA receptors might indicate a particular role of the latter in the regulation of DA metabolism. On the other hand, the antagonism against haloperidol's enhancing effect on DA metabolism by clonidine suggests a modulatory NA influence on DA transmission. The observation that clonidine reduced the effects of yohimbine and piperoxane to a lesser degree than that of haloperidol, is in agreement with this notion.Part of this work has been presented at the 13th Meeting of the Union of Swiss Societies of Experimental Biology, Lausanne, March 26/27. 1981 (for abstract see Waldmeier and Bischoff, 1981).     

Absence of dopamine sensitive adenylate cyclase in the A10 region, the origin of mesolimbic dopamine neurones.

Dopamine (DA) failed to stimulate the adenylate cyclase of the mesolimbic A10 DA nerve cell body area, in contrast to tis activating effect in the nigrostriatal A9 DA cell body area. The enzyme was stimulated by GMPPNP (a GTP analog) and NaF. This indicates the absence in the A 10 cell area of DA receptors with functional coupling on adenylate cyclase, in contrast to the A9 cell area where such DA receptors are believed to be located on afferent axon terminals.     

Studies on GABA accumulation induced byγ-glutamyl-hydrazide in regions of rat brain following treatment with a tyrosine hydroxylase inhibitor and 6-hydroxy-dopamine

Summary Reduction of DA receptor activity via depletion of DA stores does not seem to influence GABA turnover in the forebrain and in the DA cell body rich region of the midbrain.This work was supported by a grant (MH25504-03) from the National Institute of Health, USA, and by Magn. Bergvalls Stiftelse and Funds from the Karolinska Institute, Stockholm, Sweden.     

L-threo-3,4-dihydroxyphenylserine,a noradrenaline precursor,inhibits dopamine release and metabolism in the rat striatum in vivo

The effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on dopamine (DA) release and metabolism in the striatum was studied in freely moving rats by intracerebral microdialysis techniques. The DA level as well as the levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly decreased 140 min after the administration of L-threo-DOPS (50 mg/kg intraperitoneally). The results suggest that L-threo-DOPS inhibits the release and metabolism of DA in the striatum.     

L-threo-3,4-dihydroxyphenylserine, a noradrenaline precursor, inhibits dopamine release and metabolism in the rat striatum in vivo.

The effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on dopamine (DA) release and metabolism in the striatum was studied in freely moving rats by intracerebral microdialysis techniques. The DA level as well as the levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly decreased 140 min after the administration of L-threo-DOPS (50 mg/kg intraperitoneally). The results suggest that L-threo-DOPS inhibits the release and metabolism of DA in the striatum.     

The effect of dimethyl sulfoxide on tissue distribution of gentamicin

Summary Dimethyl sulfoxide (DMSO) and gentamicin were administered to rats i.p. No significant differences in gentamicin tissue concentrations were found between rats receiving DMSO and gentamicin, and rats receiving gentamicin alone. DMSO does not increase the tissue concentrations of gentamicin.     

Dopamine in the visual cortex of the cat

The endogenous content of noradrenaline (NA) and dopamine (DA) was determined by radioenzymatic assays in three different areas of the occipital (visual) cortex, in normal cats as well as in DA-deafferented animals. The use of HPLC methodology enabled us to detect and measure in addition two metabolites of DA: 3, 4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), thus confirming the existence of a DA innervation in this cortical region.     

An evaluation of apomorphine action on doapminergic receptors.

The controversial literature reports leave open a question whether apomorphine (APO) and dopamine (DA) share a common receptor? After careful evlauation of the arguments, both for and against, about direct action of APO on DA receptor we propose that rigid molecules like APO hold trans-cisoid conformation and preferably interact with the pre-synaptic DA receptors while ADTN (2-amino-6,7-dihydroxy, 1,2,3,4-tetrahydrxonaphthalene) incorporates trans-transcoid conformation and primarily acts on post-synpatic DA receptors. Dopamine, by virtue of its molecular flexibility, can act on both the receptors.     

Long-term depressor effects of catecholamine neuronal grafts in the third ventricle of the brain in normotensive rats

Neuronal tissue containing A-6 group noradrenalin (NA) neurons of the locus ceruleus, or A-10 group dopamine (DA) neurons of the substantia nigra, was grafted into the third ventricle at the level of the preoptic-anterior hypothalamic region, in normotensive male rats. A significant and long-lasting depressor effect was shown in rats with either graft. In rats with an NA neuron-rich graft, plasma concentrations of arginine-vasopressin (AVP), plasma renin activity (PRA), and corticosterone (CS) decreased significantly, whereas in rats with a DA neuron-rich graft, AVP and PRA concentrations also decreased significantly but CS showed no significant change. Neither NA nor adrenalin in plasma changed significantly in rats with either graft.     

Long-term depressor effects of catecholamine neuronal grafts in the third ventricle of the brain in normotensive rats

Summary Neuronal tissue containing A-6 group noradrenalin (NA) neurons of the locus ceruleus, or A-10 group dopamine (DA) neurons of the substantia nigra, was grafted into the third ventricle at the level of the preoptic-anterior hypothalamic region, in normotensive male rats. A significant and long-lasting depressor effect was shown in rats with either graft. In rats with an NA neuron-rich graft, plasma concentrations of arginine-vasopressin (AVP), plasma renin activity (PRA), and corticosterone (CS) decreased significantly, whereas in rats with a DA neuron-rich graft, AVP and PRA concentrations also decreased significantly but CS showed no significant change. Neither NA nor adrenalin in plasma changed significantly in rats with either graft.     

Effect of dimethyl sulfoxide on RNA synthesis in S-180 tumor cells

Zusammenfassung Es hat sich gezeigt, dass Dimethyl-Sulfoxid (DMSO) die RNA-Synthese in Sarkom 180 Tumorzellen in vitro hemmt. In 15% DMSO betrug die Syntheserate nur 7% der Kontrolle. Diese Hemmung war leicht reversibel durch einfaches Entfernen des Wirkstoffes durch Auswaschen der Zellen mit Tyrodes-Lösung. Nach Entfernung des DMSO wurde eine leicht erhöhte Aktivität der Synthese beobachtet. Die Angaben wurden mit der Kinetik der Hemmung von DNA-Synthese verglichen und ihre möglichen Beziehungen zu anderen Wirkungen von DMSO beschrieben.     

Supersensitivity after intraventricular 6-hydroxydopamine: Relation to dopamine depletion

Summary 6-Hydroxydopamine increased behavioral response to L-DOPA in proportion to the decrease of dopamine (DA) and DA uptake in rat striatum. The increased response to apomorphine, however, only occurred after >80% DA loss. Thus, 6-hydroxydopamine may induce postsynaptic changes only following large lesions.Supported in part by USPHS grants No. MH-00058 and MH-20620. We thank Kathleen Hays, Suzanne Wuerthele and Dennis McKeag for technical assistance.     

Studies on chemically induced tumors in rats: I. Heterogeneity of tumor cells and establishment of syngeneic, tumor-specific cytotoxic T cell clones

Sarcoma P1 was induced in DA rats by DMBA. Anti-P1 antibodies were produced in DA rats, purified via fixed tumor cells and used to induce anti-idiotypic antibodies in syngeneic rats. The anti-idiotypic antibodies were used to generate cytotoxic, P1 specific DA T cells in vitro. These cytotoxic T cells and P1 tumor cells were cloned by limiting dilution. Using the DA anti-P1 specific cytotoxic T cell clones, we were able to characterize 2 types of P1 tumor cell clones, namely those which were susceptible and those which were resistant to the P1 specific cytotoxic T cells. Cytotoxic T cell injected i.v. into syngeneic DA rats could not prevent the development of lethal P1 tumors.     

Respective effects on locomotor activity of injections of 5, 7-DHT in median raphe nucleus and of 6-OHDA in the mesolimbic dopaminergic group area in the rat]

This experiment was performed in order to demonstrate that the locomotor hyperactivity provoked by a radiofrequency lesion of the ventral mesencephalic tegmentum-A10 DA group area was not due to a 5-HT fiber damage. Four groups of Rats were used. First groups II and IV received a 5, 7-DHT injection in the median raphe; groups I and III received the vehicle. Locomotor activity was measured in a circular corridor 10 and 30 days; no hyperactivity was obtained. Then the same groups received a 6-OHDA injection, bilaterally in the A 10 area (groups III and IV) or the vehicle (groups I and II); the activity was measured 10 days later: significant hyperactivity was obtained with groups III and IV, without statistical differences between these two groups. In conclusion (i) 5-HT neurons are not directly involved in the VMT-hyperactivity, (ii) the DA A 10 neurons seem to be a critical anatomical target for this symptom.     

Effects of low temperatures on survival of frozen-thawed mouse embryos

Summary Almost no damage to mouse morulae was observed between 0 and –40°C, and freezing damage to embryos in DMSO, glycerol or ethylene glycol occurred after exposure to –60, –50 or –50°C, respectively. Cooling embryos in DMSO or glycerol to temperatures below –50 to –60°C increased freezing damage. To the contrary, in the presence of ethylene, glycol, no more damage occurred after exposure to temperatures below –50°C.     

An effect of DMSO on post-irradiation saccharin avoidance in mice

Zusammenfassung Ein Dimethylsulfoxyd (DMSO)-Effekt wird beschrieben: bei Nachbestrahlung vermeiden Mäuse Sodium-Saccharin. Mit DMSO vorbehandelte Tiere (Eintauchen der Schwänze in diese Substanz kurz vor Bestrahlung) bevorzugen wie unbehandelte Mäuse Saccharin-Sodium.

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This work was supported in part by Grant No. PHS-SOI-FR-5369-04-5 from the University of Illinois, Graduate College of Medicine.     

Methadone and brain development

Summary The effect of maternally administered methadone hydrochloride (5 mg/kg) on brain development of off-spring treated during gestation and/or lactation was studied in 21-day-old rats. Animals treated during gestation or lactation were the most severely affected, with reductions in brain weights (12% and 30%,respectively), and DNA values (50% and 34%, respectively) observed.The assistance of Eileen J. Zagon is gratefully acknowledged. This research was supported in part by American Cancer Society grant PDT-27B and NIDP grant DA01618-01.