Does the reversal of the anticonflict effect of phenobarbital by beta-CCE and FG 7142 indicate benzodiazepine receptor-mediated anxiogenic properties?

In mice and rats, the high affinity ligand for brain benzodiazepine (BZ) receptors beta-CCE, and the more stable congener FG 7142, failed to exert anticonflict activity in conflict situations but instead reversed the anticonflict effect of lorazepam. In contrast to Ro 15-1788, beta-CCE and FG 7142 also antagonized the anticonflict effect of phenobarbital in rats. This effect suggests that beta-CCE and FG 7142 may produce anxiety by either inducing a conformational change in the BZ receptors which is directly opposite to that induced by the benzodiazepines, or binding to a particular subclass of BZ receptors.

Osteosclerosis of the femoral head in long-term uraemic rabbits

The morphology of the femoral head of rabbits was studied by histomorphometric analysis of undecalcified sections after four and eight months' duration of surgically induced chronic renal failure. A significant increase in trabecular bone mas and osteoid tissue was found in the uraemic rabbits. Signs of osteonecrosis or increase bone resorption were not seen. 99mTechnetium-methylenediphosphonate osteoscintigrams showed increased uptake in the axial skeleton and all periarticular regions in uraemic rabbits. The serum concentrations of calcium and phosphate in the uraemic rabbits were increased.

Interaction of convulsive ligands with benzodiazepine receptors

The gamma-aminobutyric acid (GABA)-benzodiazepine receptor complex, which is composed of distinct proteins embedded in the neuronal plasma membrane, is important for several effects of benzodiazepines, including protection afforded against convulsions. During structural modification of ethyl beta-carboline-3-carboxylate an agent was discovered which has high affinity for brain benzodiazepine receptors but which is a potent convulsant. Also in contrast to benzodiazepines, this type of benzodiazepine receptor ligand favors benzodiazepine receptors in the non-GABA-stimulated conformation, which may explain the convulsive properties.

Peripheral metabolism of beta-carboline-carboxylic acid esters

Esters of beta-carboline-3-carboxylic acid have recently been identified as potent inhibitors of brain benzodiazepine receptors in vitro. Ethyl beta-carboline-3-carboxylate (beta-CCE), however, is a rather weak inhibitor in vivo of benzodiazepine receptors in mice. The ED50-value was 91 mg/kg intraperitoneally 35 min after administration (ED50 is that dose which inhibits by 50% the specific binding of 3H-flunitrazepam intravenously). ED50 for beta-CCE was 2-20 fold lower in mice pretreated with organophosphorus esterase inhibitors, concomitantly with the observation of strong inhibition of liver and kidney hydrolyzing activity, using 3H-propyl beta-carboline-3-carboxylate as substrate. The rat brain contains only approximately 0.1% of the hydrolyzing activity as compared to the liver. It is concluded that some esters of beta-carboline-3-carboxylate exhibit only weak effects on benzodiazepine receptors in living animals due to hydrolysis outside the brain.

The benzodiazepine/GABA receptor complex during severe ethanol intoxication and withdrawal in the rat

The benzodiazepine/GABA (gammaaminobutyric acid) receptor complex was investigated during severe ethanol intoxication and withdrawal in the rat. The intragastric intubation technique was used to establish physical ethanol dependence in the animals. Cerebral cortex from male Wistar rats was studied 1) after 3 1/2 days of severe ethanol intoxication, 2) during the ethanol withdrawal reaction and 3) in a control group. The effect of GABA-ergic activation by muscimol and THIP (4,5,6,7-tetrahydroisoxazole(5,4-c)pyridin-3-01) on 3H-diazepam binding was unchanged during ethanol intoxication and withdrawal, as was the affinity constant (KD) and the maximal number of binding sites (Bmax) for 3H-flunitrazepam. In conclusion, the benzodiazepine/GABA receptor complex is unlikely to play any causal part in physical ethanol dependence.

Basement membrane changes in breast cancer detected by immunohistochemical staining for laminin

The distribution of the basement membrane glycoprotein laminin was studied by the immunoperoxidase technique in benign and malignant human breast tissue and in axillary lymph nodes from patients with breast cancer. An antiserum prepared against rat laminin was used. The specificity of this antiserum against human laminin was studied using the FL cell line of human epithelial-like cells derived from normal amniotic membrane. The antiserum reacted with these cells in immunoperoxidase staining and precipitated metabolically labeled secreted polypeptides which comigrated with polypeptides with molecular weights of 400,000 and 200,000 of rat laminin in sodium dodecyl sulfate:polyacrylamide gel electrophoresis. The neoplastic cells in malignant breast tissues showed strong cytoplasmic staining for laminin, and a positive reaction was aslo found in lymph node metastases. In some cases in which only micrometastases were present, these cells also stained strongly for laminin. In nonmalignant breast tissues, the epithelial cells of the duct were positive for laminin, but the staining was weaker than in the carcinomas. Pretreatment of the fixed tissue sections with trypsin markedly enhanced the staining of basement membranes for laminin. In trypsin-treated sections of normal breast tissue and benign lesions, the laminin staining delineated continuous basement membranes. In carcinomas representing the more differentiated types, basement membranes presumably produced by the tumor cells could be revealed by laminin staining, but they were thinner and discontinuous. The poorly differentiated carcinomas lacked organized basement membranes detectable by laminin staining. Our studies suggest that staining for laminin may be a useful adjunct test for detection of micrometatases in lymph nodes. The correlation of disintegration of the laminin-containing basement membranes of tumors with increasingly anaplastic appearance supports the notion that basement membranes may play a role in tumor invasion.

[3H]Propyl beta-carboline-3-carboxylate as a selective radioligand for the BZ1 benzodiazepine receptor subclass

Ethyl beta-carboline-3-carboxylate (beta-CCE) is a mixed-type inhibitor of [3H]flunitrazepam ([3H]FNM) binding to benzodiazepine receptors in noncerebellar regions of rat brain. These findings may represent the presence of either receptor multiplicity or negative cooperativity among benzodiazepine receptors. [3H]Propyl beta-carboline-3-carboxylate ([3H]PrCC) has previously been shown to bind specifically to benzodiazepine receptors of rat cerebellum. In the present study we found no indication of the presence of true negative cooperativity among benzodiazepine receptors when [3H]PrCC was used as radioligand. However, we observed that [3H]PrCC labelled only 57% of [3H]FNM binding sites in rat hippocampus (Bmax values) and 71% in rat cerebral cortex, whereas the number of receptors labelled by both ligands was equal in the cerebellum. Hofstee analyses of the shallow inhibition curves seen in hippocampus and cerebral cortex when [3H]FNM binding was inhibited by beta-CCE indicate that beta-CCE and some other beta-carboline-3-carboxylate derivatives interact preferentially with a subclass of receptors, and that the percentage of this subclass is equivalent to the number of receptors labelled by [3H]PrCC. We conclude that [3H]PrCC at low concentration (0.3-0.4 X 10(-9) M) labels a subclass of benzodiazepine receptors, BZ1, while another class, BZ2 receptors, are not labelled by [3H]PrCC when filtration assays are used. By parallel determinations of the proportion between [3H]FNM and [3H]PrCC binding we calculated the percentage of BZ1 receptors in several regions of rat, guinea pig and calf brain and in mouse forebrain. The values ranged from approximately 50% in hippocampus to 90% in the guinea pig pons.

Metastases to the breast from extramammary carcinomas

Metastases to the breast from extramammary carcinomas are rare. Only about 200 cases are reported in the literature. Fifteen additional cases are presented here and the literature is reviewed. Two of the patients has primary thyroid carcinoma, two adenocarcinoma of the colon, three bronchogenic carcinoma, four malignant melanoma, one a squamous cell carcinoma of the oesophagus, one an adenocarcinoma of the stomach, one a renal cell carcinoma and one a carcinoid of the terminal ileum. In three cases the breast lesion was the first manifestation of an extramammary cancer. Six of the patients died of disseminated cancer shortly after the breast metastasis was diagnosed. Although breast metastasis may be suspected clinically, exact histological diagnosis is important in order to avoid unnecessary surgical treatment and to guide further therapy.

[3H]propyl beta-carboline-3-carboxylate binds specifically to brain benzodiazepine receptors

Ethyl beta-carboline-3-carboxylate has recently been isolated from human urine and it was proposed that derivatives of this compound might be related to an endogenous ligand for benzodiazepine receptors. In the present study we investigated high-affinity binding of [3H]propyl beta-carboline-3-carboxylate ([3H]PrCC) to rat brain membranes. [3H]PrCC binds specifically and with high affinity (half-maximal binding at ca. 1nM) to rat brain membranes. The regional and subcellular distributions of specific [3H]PrCC binding are similar, but not identical, to the distributions of [3H]flunitrazepam or [3H]-diazepam binding. The total numbers of binding sites labelled by [3H]PrCC and [3H]flunitrazepam in rat cerebellum are closely similar, and both ligands bind to cerebellar membranes in a mutually exclusive way. The pharmacological selectivity of [3H]PrCC and [3H]diazepam binding is almost identical. Binding of [3H]PrCC like binding of [3H]diazepam, can be increased in vitro by muscimol, GABA and SQ 20.009. Although subtle differences in binding characteristics were observed, these results indicate that [3H]PrCC and benzodiazepines bind to a common recognition site on benzodiazepine receptors.

Decreased spiroperidol and LSD binding in rat brain after continuous amphetamine

Rats were implanted with a silicone tubing pellet continuously releasing amphetamine base for several days. After five days of this treatment specific binding of spiroperidol (dopamine receptors) and LSD (serotonin receptors) was decreased in the corpus striatum and frontal cortex. In the striatum the number of dopamine receptors was decreased while the affinity was unchanged. These results indicate that dopamine and serotonin receptors can be regulated by the release of their own neurotransmitter.

Ethyl beta-carboline-3-carboxylate shows differential benzodiazepine receptor interaction

High-affinity binding of 3H-diazepam and 3H-flunitrazepam has provided evidence for the presence of benzodiazepine receptors on brain neurones. Pharmacological evidence showing a clear correlation between receptor affinity and in vivo pharmacological potency for several benzodiazepines and a link between benzodiazepine receptors and GABA (gamma-amino-butyric acid) receptors at the molecular level, indicates that these receptors are relevant to the pharmacological and clinical effects of benzodiazepines. In searching for possible endogeneous ligands for benzodiazepine receptors we have recently isolated ethyl beta-carboline-3-carboxylate (beta-CCE) found human urine and brain, and shown that beta-CCE has a higher affinity than diazepam for brain benzodiazepine receptors. beta-CCE itself is probably not present in the brain, but may be closely related to an endogenous benzodiazepine receptor ligand. We report here that beta-CCE, in contrast to benzodiazepines, can distinguish clearly between benzodiazepine receptors in cerebellum and hippocampus. This result strongly indicates that benzodiazepine receptors are not a single class of non-interacting entities. It has not been possible to determine whether two distinct receptors are present and/or whether true negative cooperativity exists among hippocampal, but not cerebellar, benzodiazepine receptors.

Experiments with radiopaque perfluorocarbon emulsions for selective opacification of organs and total body angiography

Emulsions of radiopaque perfluorocarbon with small particle size were prepared by sonication and concentrated by centrifugation. The emulsions were well tolerated when given intravenously to rats in a dose up to 20 ml/kg. Whole-body angiograms were obtained for up to 6 hours after injection with visualization of vessels smaller then 1 mm. Hepatosplenograms were obtained after 2 hours and for several days after injections of radiopaque perfluorocarbon. Contrast enhancement was also seen in the myocardium, ovaries, adrenal glands, and intestines with brominated perfluorocarbon emulsions.

Urinary and brain beta-carboline-3-carboxylates as potent inhibitors of brain benzodiazepine receptors

Benzodiazepines probably exert their anxiolytic, hypnotic, and anticonvulsant effects by interacting with brain-specific high-affinity benzodiazepine receptors. In searching for possible endogenous ligands for these receptors we have purified a compound 10(7)-fold from human urine by extractions, treatment with hot ethanol, and column chromatography. The compound was identified as beta-carboline-3-carboxylic acid ethyl ester (IIc) by mass spectrometry, NMR spectrometry, and synthesis; IIc was also isolated from brain tissues (20 ng/g) by similar procedures. Very small concentrations of IIc displaced [3H]diazepam completely from specific cerebral receptors, but not from liver and kidney binding sites; the concentration causing 50% inhibition of specific [3H]diazepam binding (IC50) was 4-7 nM compared to ca. 5 nM for the potent benzodiazepine lorazepam. Specific binding sites for quinuclidinyl benzilate, naloxone, spiroperidol, serotonin, muscimol, and WB 4101 were not affected by IIc. In contrast to benzodiazepines, IIc exhibits "mixed type" competitive inhibition of forebrain benzodiazepine receptors (negative cooperativity). We surmise that an endogenous ligand for benzodiazepine receptors may be a derivative of beta-carboline-3-carboxylic acid.

Method of estimating the disposition of drugs in the Danish population by sampling reimbursed prescriptions

A method by which for a small cost it is possible to obtain a quantitative expression for the utilization, disposition and cost of drugs in a Danish county of 500,000 inhabitants. The procedure makes it possible to follow reimbursed preparations, i. e., drugs considered essential for the treatment of diseases. The sale, in D kr., of reimbursed preparations to individuals comprises about 80% of the sale of preparations requiring prescription. And in turn the sale of the latter amounts to 80% of total drug sales to single subjects. The method is based on systematic utilization of all the information available on each prescription; concepts of 'Entry Parameters', 'Calculated Units' and 'Derived Units' was discussed; the 'units' concern frequency of prescription and age- and sex specific dose-frequencies (weight units or defined daily doses -- DDD's). The possibility of creating a base for calculation of the frequency of certain diseases and of side-effects of drugs is mentioned, and examples of the application of the method to certain categories of patients and to certain drugs are given. From limitations of the method it is concluded that it should be considered as a supplement to other complete methods for the study of drug consumption.

Benzodiazepine receptors in the brain as affected by different experimental stresses: the changes are small and not undirectional

Rats and mice were exposed to several different stress situations to investigate whether brain benzodiazepine receptors were sensitive to altered external or internal environmental circumstances. All stresses were applied for several days. Electrical foot shock and post-natal isolation of newborn pups resulted in small (7--25%; P less than 0.05--0.001) decreases in benzodiazepine receptor binding in some cerebral cortex or hippocampal areas while immobilization stress resulted in a small (9%; P less than 0.05) increase in frontal cortex. Other brain areas (i.e., striatum, cerebellum, pons-medulla, and occipital cortex) and other stress forms (isolation of male mice, forced swimming in cold water, or chronic amphetamine intoxication) did not change receptor binding. The effect of prolonged stress on benzodiazepine receptors is complex and not very pronounced.

Granular cell myoblastoma in the parotid gland

Granular cell myoblastomas develop most commonly in the head and neck region, but their occurrence in the salivary glands has been reported in only one case, in the submaxillary gland. The authors report a case of granular cell myoblastoma in a previously undescribed localization, the parotid gland.

Neuronal localisation of benzodiazepine receptors in cerebellum

The cellular localisation of benzodiazepine receptors was studied. Kainic acid induced neuronal lesions (2 x 0.25-2 x 2 micrograms; 2-26 days in rat cerebellum decreased specific binding of [3H]flunitrazepam down to 35% of controls. Specific binding of [3H]flunitrazepam was also decreased (to 80% of controls) in the cerebllum of mutant nervous mouse (nr/nr) where Purkinje cells are degenerated but in the mutant weaver mouse where granule cells are degenerated. These results show that benzodiazepine receptors are located mainly on neurons; both on Purkinje cells and other neurons, but not to a great extent on granule cells.