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1.
Eur J Endocrinol ; 184(1): R17-R28, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33112274

ABSTRACT

ABSTRACT: This review aims to cover the subject of sex steroid action in adolescence. It will include situations with too little sex steroid action, as seen in for example, Turners syndrome and androgen insensitivity issues, too much sex steroid action as seen in adolescent PCOS, CAH and gynecomastia, too late sex steroid action as seen in constitutional delay of growth and puberty and too early sex steroid action as seen in precocious puberty. This review will cover the etiology, the signs and symptoms which the clinician should be attentive to, important differential diagnoses to know and be able to distinguish, long-term health and social consequences of these hormonal disorders and the course of action with regards to medical treatment in the pediatric endocrinological department and for the general practitioner. This review also covers situations with exogenous sex steroid application for therapeutic purposes in the adolescent and young adult. This includes gender-affirming therapy in the transgender child and hormone treatment of tall statured children. It gives some background information of the cause of treatment, the patient's motivation for medicating (or self-medicating), long-term consequences of exogenous sex steroid treatment and clinical outcome of this treatment.


Subject(s)
Endocrine System Diseases/metabolism , Gonadal Steroid Hormones/metabolism , Puberty, Precocious/metabolism , Puberty/metabolism , Adolescent , Adolescent Health , Endocrine System Diseases/drug therapy , Female , Gonadal Steroid Hormones/therapeutic use , Humans , Male , Puberty, Precocious/drug therapy , Young Adult
2.
J Infect ; 81(2): e39-e45, 2020 08.
Article in English | MEDLINE | ID: mdl-32504735

ABSTRACT

OBJECTIVES: SARS-CoV-2 antibody assays are needed for serological surveys and as a complement to molecular tests to confirm COVID-19. However, the kinetics of the humoral response against SARS-CoV-2 remains poorly described and relies on the performance of the different serological tests. METHODS: In this study, we evaluated the performance of six CE-marked point-of-care tests (POC) and three ELISA assays for the diagnosis of COVID-19 by exploring seroconversions in hospitalized patients who tested positive for SARS-CoV-2 RNA. RESULTS: Both the ELISA and POC tests were able to detect SARS-CoV-2 antibodies in at least half of the samples collected seven days or more after the onset of symptoms. After 15 days, the rate of detection rose to over 80% but without reaching 100%, irrespective of the test used. More than 90% of the samples collected after 15 days tested positive using the iSIA and Accu-Tell® POC tests and the ID.Vet IgG ELISA assay. Seroconversion was observed 5 to 12 days after the onset of symptoms. Three assays suffer from a specificity below 90% (EUROIMMUN IgG and IgA, UNscience, Zhuhai Livzon). CONCLUSIONS: The second week of COVID-19 seems to be the best period for assessing the sensitivity of commercial serological assays. To achieve an early diagnosis of COVID-19 based on antibody detection, a dual challenge must be met: the immunodiagnostic window period must be shortened and an optimal specificity must be conserved.


Subject(s)
Antibodies, Viral/blood , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Enzyme-Linked Immunosorbent Assay , Pneumonia, Viral/diagnosis , Point-of-Care Systems , Seroconversion , Adolescent , Adult , Aged , Aged, 80 and over , Betacoronavirus/immunology , COVID-19 , COVID-19 Testing , Coronavirus Infections/immunology , Female , Hospitalization/statistics & numerical data , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/immunology , Reagent Kits, Diagnostic , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests , Young Adult
3.
Neuropharmacology ; 23(2A): 169-73, 1984 Feb.
Article in English | MEDLINE | ID: mdl-6717757

ABSTRACT

Two epimer quinoline derivatives, PK 5078 and PK 7059, have been shown to be potent at releasing 5-HT from blood platelets. Moreover PK 5078 was also a potent and selective inhibitor of the uptake of 5-HT, being about 20 times as active as clomipramine. Both drugs, like p-chloroamphetamine, released 5-HT but did not inhibit MAO-A. Whilst p-chloroamphetamine seemed to be active on the cytoplasmic pool of 5-HT and reserpine on the vesicular pool, PK 5078 and PK 7059 were effective first on the vesicular pool and then on the cytoplasmic pool. The quinoline derivatives were devoid of the typical side-effects of amphetamine-like drugs, i.e. hyperactivity, anorexia and group toxicity. For these reasons PK 5078 and PK 7059 can be considered to be a new type of selective 5.HT-releasing drug.


Subject(s)
Quinolines/pharmacology , Serotonin/metabolism , Animals , Blood Platelets/metabolism , Brain/metabolism , Dopamine/metabolism , Humans , In Vitro Techniques , Male , Monoamine Oxidase/metabolism , Myocardium/metabolism , Norepinephrine/metabolism , Rats , Rats, Inbred Strains , Stereoisomerism , Synaptosomes/metabolism , p-Chloroamphetamine/pharmacology
4.
J Med Chem ; 29(8): 1394-8, 1986 Aug.
Article in English | MEDLINE | ID: mdl-3016265

ABSTRACT

A series of 4-amino-6-chloro-2-piperazinopyrimidines were synthesized and evaluated for their ability to interact with alpha 1- and alpha 2-adrenoceptors in vitro in binding assays using [3H]WB-4101, [3H]clonidine, and [3H]idazoxan as radioligands. Some compounds were also tested as inhibitors of [3H]spiroperidol binding. Several members of this series showed high and selective affinity for alpha 2-adrenoceptors. The nature of the 4-amino substituent seems to be the most critical factor in determining the potency at these receptors.


Subject(s)
Piperazines/metabolism , Pyrimidines/metabolism , Receptors, Adrenergic, alpha/metabolism , Animals , Binding, Competitive , Cerebral Cortex/metabolism , Clonidine/metabolism , Corpus Striatum/metabolism , Dioxanes/metabolism , Idazoxan , Rats , Spiperone/metabolism , Structure-Activity Relationship
5.
Biochem Pharmacol ; 34(2): 167-70, 1985 Jan 15.
Article in English | MEDLINE | ID: mdl-2981532

ABSTRACT

"Peripheral type" benzodiazepine binding sites have been solubilized with digitonin. Binding site density for the solubilized material is increased 1.7 times compared to membranes. A decrease in the affinity for [3H]-PK 11195 (a new ligand for the peripheral type benzodiazepine binding sites) was also observed. Pharmacological specificity of displacing agents was conserved during solubilization. The apparent molecular weight determined by gel filtration was 215,000 +/- 20,000. The high Bmax value of the solubilized preparation (greater than 50 pmole/mg protein) makes it advantageous as the starting point for a purification procedure.


Subject(s)
Adrenal Glands/analysis , Isoquinolines/metabolism , Receptors, GABA-A/isolation & purification , Animals , Male , Molecular Weight , Rats , Rats, Inbred Strains , Receptors, GABA-A/analysis , Solubility , Tritium
6.
Biochem Pharmacol ; 33(15): 2467-72, 1984 Aug 01.
Article in English | MEDLINE | ID: mdl-6087829

ABSTRACT

Peripheral type benzodiazepine binding sites have been studied in human and rat platelets and platelet membranes by using PK 11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methyl propyl)-3-isoquinolinecarboxamide) as a ligand. [3H]PK 11195 binding to the intact cells and membranes is saturable, with a high affinity and presents the pharmacological specificity corresponding to the peripheral binding sites (PK 11195 greater than RO5-4864 greater than diazepam greater than clonazepam). [3H]PK 11195 affinity is not affected by cell lysis, but there is a loss of binding capacity, contrarily to RO5-4864 whose affinity is greatly diminished. For this reason [3H]RO5-4864 binding can only be demonstrated in intact cells. Furthermore opposite to RO5-4864, PK 11195 affinity is not decreased by increasing temperatures. No difference was found between binding parameters (KD and Bmax) for [3H]PK 11195 between normotensive and hypertensive subjects. The very high binding capacity of human and rat platelets (Bmax greater than pmole/10(8) cells) makes them a good biological model for studying the physiological significance of "peripheral type" benzodiazepine binding sites.


Subject(s)
Blood Platelets/metabolism , Hypertension/blood , Isoquinolines , Receptors, Cell Surface/metabolism , Adult , Animals , Benzodiazepinones/blood , Binding, Competitive , Cell Membrane/metabolism , Female , Humans , In Vitro Techniques , Isoquinolines/blood , Male , Middle Aged , Rats , Receptors, GABA-A
7.
Infect Control Hosp Epidemiol ; 22(5): 273-8, 2001 May.
Article in English | MEDLINE | ID: mdl-11428436

ABSTRACT

OBJECTIVE: To compare three methods for assessing the excess nurse work load related to recommended procedures for managing nosocomial infections (NI) due to multiresistant bacteria (MRB): two activity scores, the Omega score and the Projet de Recherche en Nursing (PRN) system, and a specific evaluation based on functional analysis of nursing procedures. SETTING: 10 beds in a medical intensive care unit (MICU). PATIENTS: Patients admitted from November 15, 1995, to June 15, 1996, were included and divided in two groups based on presence of MRB colonization or infection (MRB+ and MRB-groups). METHODS: Data were collected regarding length of stay (LOS) in days; Omega score for the entire stay; PRN score for the entire stay and per day; and time required to perform correctly four nursing procedures related to MRB NI, as evaluated specifically by the nursing staff, using a detailed functional analysis document that described all elementary nursing tasks in chronological order and all material needed to carry out those tasks. RESULTS: The LOS and total Omega and PRN scores were higher in the MRB+ group than in the MRB- group: LOS, 23 +/- 20.6 versus 12 +/- 15.3 days, (P<.001); Omega score, 164 +/- 103.4 versus 123 +/- 93.7 points (P<.001); PRN score, 3,606 +/- 3,187 versus 1,854 +/- 2,356 points (P<.001), respectively. The daily PRN score was also higher in MRB+ group (PRN, 160 +/- 25 vs 146 +/- 34 points in the MRB- group; P<.028). Four nursing procedures made necessary by MRB acquisition were identified: isolation precautions, with two levels according to whether the risk of contamination was mild-moderate or high; bathing the patient with antiseptic solution; bedpan management; and microbiological screening. The functional analysis indicated that the time needed to carry out these four procedures correctly was 245 minutes per patient per day, as compared to 85 minutes according to the PRN system. CONCLUSIONS: Our data confirm that MRB NIs are responsible for an increase in nurse work load, as estimated by LOS, Omega, and PRN scores. However, the daily excess nurse work load related directly to recommended procedures for managing MRB NIs in MICUs is underestimated by these activity scores, as compared to a specific functional analysis of nursing tasks. This may be of importance in evaluating potential links between nurse work load and MRB NIs and in determining the number of nurse hours needed to comply with infection control recommendations.


Subject(s)
Cross Infection/nursing , Intensive Care Units , Workload/statistics & numerical data , Cross Infection/microbiology , Cross Infection/prevention & control , Drug Resistance, Microbial , Female , Humans , Infection Control/methods , Intensive Care Units/statistics & numerical data , Length of Stay/statistics & numerical data , Male , Middle Aged , Retrospective Studies , Statistics, Nonparametric , Workforce
8.
Eur J Pharmacol ; 112(2): 257-60, 1985 Jun 07.
Article in English | MEDLINE | ID: mdl-2992998

ABSTRACT

PK 11195, an antagonist of peripheral type benzodiazepine receptors, in doses from 5 to 25 mg/kg i.d. protected in a dose-dependent manner dogs against both early and delayed ventricular arrhythmias induced by 20 min ischemia and against ventricular fibrillation following reperfusion. Thus, peripheral-type benzodiazepine receptors might represent a novel target in the treatment of angina and cardiac ischemia.


Subject(s)
Anti-Arrhythmia Agents , Coronary Disease/physiopathology , Isoquinolines/pharmacology , Receptors, GABA-A/drug effects , Animals , Blood Pressure/drug effects , Coronary Disease/complications , Dogs , Dose-Response Relationship, Drug , Female , Male
9.
Eur J Pharmacol ; 128(3): 269-72, 1986 Sep 09.
Article in English | MEDLINE | ID: mdl-3024996

ABSTRACT

The specific binding of [3H]PK 11195 to the peripheral-type benzodiazepine binding site is inhibited by the l-enantiomer of N,N-diethyl-alpha-methyl-2-phenyl-4-quinolinepropanamide ((-)Q1) but not by its d-enantiomer ((+)Q1). (-)Q1 inhibited [3H]PK 11195 binding to several rat tissues with an IC50 of less than 10 nM whereas (+)Q1 was at least 500 times less potent. This stereoselectivity was observed in all the tissues tested (brain, heart, kidney and adrenals). The same stereoselectivity was found for the displacement of the binding of [3H]PK 11195 in vivo, where (-)Q1 had an ID50 between 4-15 mg/kg and (+)Q1 was completely inactive at all doses tested (i.e. up to 40 mg/kg). Neither isomer had appreciable affinity for central-type benzodiazepine binding sites ([3H]diazepam) nor for voltage-sensitive calcium channels ([3H]PN 200210 and [3H]verapamil).


Subject(s)
Isoquinolines/metabolism , Quinolines/pharmacology , Receptors, GABA-A/metabolism , Adrenal Glands/metabolism , Animals , Brain Chemistry/drug effects , Female , In Vitro Techniques , Kidney/metabolism , Myocardium/metabolism , Rats , Rats, Inbred Strains , Stereoisomerism
10.
Eur J Pharmacol ; 99(1): 1-7, 1984 Mar 16.
Article in English | MEDLINE | ID: mdl-6723786

ABSTRACT

'Peripheral type' benzodiazepine binding sites in several rat tissues were labelled by intravenous injection of [3H]PK 11195 and [3H] RO5 -4864. Binding was saturable in all tissues studied and regional distribution paralleled the in vitro binding. A similar potency order of displacing compounds was found in vivo and in vitro PK 11195 greater than PK 11211 greater than RO5 -4864 greater than diazepam greater than dipyridamole greater than clonazepam. These results demonstrate the feasibility of using this technique to examine the effects of pharmacological manipulation on the binding sites in their native state. However some properties (broader maximum during time course, higher percentage of particulate binding in the brain and independence of temperature) make [3H]PK 11195 the most suitable ligand for this kind of studies.


Subject(s)
Benzodiazepines/analysis , Radioligand Assay , Animals , Benzodiazepinones , Binding Sites , Brain Chemistry , Isoquinolines , Kidney/analysis , Kinetics , Male , Myocardium/analysis , Olfactory Bulb/analysis , Rats , Rats, Inbred Strains
11.
Brain Res Bull ; 13(1): 69-77, 1984 Jul.
Article in English | MEDLINE | ID: mdl-6478272

ABSTRACT

"Peripheral type" benzodiazepine binding sites were labelled in cat brain membranes by using [3H]PK 11195. This ligand binds to the "peripheral type" binding sites in a reversible, specific and saturable manner. Cat brain binding sites density (congruent to 6 pmol/mg prot.) was higher than in the rat. Pharmacological specificity was demonstrated by the potency order of displacing agents: PK 11195 greater than RO5-4864 greater than dipyridamole greater than diazepam greater than clonazepam. A similar characterization was performed in slide mounted brain sections where [3H]PK 11195 also labelled the "peripheral type" benzodiazepine binding sites. The high percentage of specific binding (80%) at 1 nM of [3H]PK 11195 made possible the autoradiographic studies on binding sites distribution. These sites were heterogeneously distributed in the grey matter and absent in white matter. Visual, auditory and other specific sensory relay stations were highly labelled. The blood pressure regulating nuclei, the vestibulo-cerebellar and the extrapyramidal motor system also presented a very high binding density. As previously described in the rat brain, choroid plexus was also strongly labelled by [3H]PK 11195 in the cat.


Subject(s)
Benzodiazepines/metabolism , Brain/metabolism , Isoquinolines/metabolism , Animals , Autoradiography , Binding Sites , Cats , Cerebellum/metabolism , Computers , In Vitro Techniques , Limbic System/metabolism , Male , Reticular Formation/metabolism , Vestibular Nerve/metabolism
12.
Life Sci ; 36(11): 1059-68, 1985 Mar 18.
Article in English | MEDLINE | ID: mdl-2983164

ABSTRACT

The effects of two drugs acting at the peripheral type benzodiazepine binding sites, PK 11195 and RO5-4864, were examined in shock-induced suppression of drinking in rats. These two compounds have opposite effects : RO5-4864 (3.1-1205 mg/kg i.p.) enhanced whereas PK 11195 (25-50 mg/kg i.p.) decreased the punished responding, and PK 11195 (6.25 mg/kg, a dose which did not alter the punished responding) blocked the proconflict action of RO5-4864 (6.25 and 12.5 mg/kg). The effects of RO5-4864 and PK 11195 were not antagonized by RO15-1788, a selective antagonist of the central benzodiazepine site. In addition, PK 11195 (6.25 mg/kg) did not reverse the proconflict effect of two beta-carbolines : beta-CEE and FG 7142. AS picrotoxin did not change the punished responding, these data imply that the effects of RO5-4864 and PK 11195 on the one hand and those of chlordiazepoxide and beta-carbolines on the other hand are differentially mediated and suggest that the peripheral type benzodiazepine binding sites are involved in this conflict model.


Subject(s)
Benzodiazepinones/pharmacology , Conflict, Psychological , Isoquinolines/pharmacology , Receptors, GABA-A/drug effects , Animals , Carbolines/pharmacology , Conditioning, Operant/drug effects , Dose-Response Relationship, Drug , Drug Interactions , Electroshock , Flumazenil , Ligands , Male , Rats , Rats, Inbred Strains
13.
Life Sci ; 39(4): 329-39, 1986 Jul 28.
Article in English | MEDLINE | ID: mdl-2426550

ABSTRACT

In a partially depolarized guinea pig papillary muscle preparation, BAY K8644 stimulated voltage-operated calcium channels, promoting slow action potentials; this effect was dose-dependent over a concentration range of 3 X 10(-7) M to 3 X 10(-6) M. Isoproterenol and histamine also induced slow action potentials by stimulating beta or H2 receptors, respectively. PK 11195, the antagonist of peripheral type benzodiazepine receptors, inhibited the effect of BAY K8644, but not those of histamine or isoproterenol. Moreover, PK 11195 "dose-dependently" antagonized the ability of RO5-4864 to inhibit the slow action potentials elicited by barium chloride. Thus, in the heart, PK 11195, an antagonist of peripheral type benzodiazepine receptors, can modulate voltage-operated calcium channels when they are activated directly, but not when they are activated by stimulation of neurotransmitter receptors.


Subject(s)
Ion Channels/drug effects , Isoquinolines/pharmacology , Nifedipine/analogs & derivatives , Receptors, Adrenergic, beta/drug effects , Receptors, GABA-A/drug effects , Receptors, Histamine H2/drug effects , Receptors, Histamine/drug effects , 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester , Action Potentials/drug effects , Animals , Barium/pharmacology , Benzodiazepinones/pharmacology , Female , Guinea Pigs , In Vitro Techniques , Isoproterenol/antagonists & inhibitors , Male , Myocardial Contraction/drug effects , Nifedipine/antagonists & inhibitors , Papillary Muscles
14.
Life Sci ; 36(4): 391-400, 1985 Jan 28.
Article in English | MEDLINE | ID: mdl-2578209

ABSTRACT

PK 11195, an antagonist of the peripheral type benzodiazepine receptor, does not affect either the duration of the action potential or the tension of the guinea pig papillary muscle. However, it antagonized the effects of the calcium channel blockers, nitrendipine, verapamil, diltiazem, and of BAY K8644, a calcium channel agonist in this heart preparation. On the other hand, PK 11195 does not change the increase in the action potential duration provoked by the potassium channel blocker tetraethylammonium. RO5-4864, an agonist of the peripheral type benzodiazepine receptor, decreased the tension of the guinea pig papillary muscle. The effect was reversed by increasing extracellular Ca2+ concentrations up to 4 mM. These results suggest that in the heart the peripheral type benzodiazepine receptors are coupled to calcium channels.


Subject(s)
Calcium/physiology , Heart/physiology , Ion Channels/physiology , Receptors, GABA-A/physiology , 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester , Action Potentials/drug effects , Animals , Calcium Channel Blockers , Diltiazem/pharmacology , Female , Guinea Pigs , Isoquinolines , Male , Myocardial Contraction/drug effects , Nifedipine/analogs & derivatives , Nifedipine/pharmacology , Nitrendipine , Tetraethylammonium Compounds/pharmacology , Verapamil/pharmacology
15.
Life Sci ; 32(16): 1839-47, 1983 Apr 18.
Article in English | MEDLINE | ID: mdl-6300588

ABSTRACT

[3H] RO5-4864 binding sites have been characterized in kidney, heart, brain, adrenals and platelets in the rat. In all these organs the following order of potency in the RO5-4864 displacement was found: RO5-4864 greater than diazepam greater than clonazepam indicating that they correspond to the "peripheral type" of benzodiazepine binding sites. PK 11195, an isoquinoline carboxamide derivative, displaces [3H] RO5-4864 from its binding sites in all the organs. PK 11195 was as potent as RO5-4864 in the platelets, heart, adrenals, kidney and several brain regions (midbrain, hypothalamus, medulla + pons and hippocampus. However it was 5 to 10 times more effective in cortex and striatum. In conclusion PK 11195 might represent a new tool to elucidate the physiological relevance of "peripheral type" benzodiazepine binding sites and might help to discriminate the hypothetical subclasses of these binding sites.


Subject(s)
Benzodiazepinones/metabolism , Isoquinolines/metabolism , Receptors, Cell Surface/metabolism , Adrenal Glands/metabolism , Animals , Blood Platelets/metabolism , Brain/metabolism , Clonazepam/metabolism , Diazepam/metabolism , In Vitro Techniques , Kidney/metabolism , Male , Myocardium/metabolism , Rats , Rats, Inbred Strains , Receptors, GABA-A , Tissue Distribution
16.
Life Sci ; 32(16): 1849-56, 1983 Apr 18.
Article in English | MEDLINE | ID: mdl-6300589

ABSTRACT

Peripheral type of benzodiazepine binding sites were labelled in the kidney, the heart and the brain with [3H] RO5-4864 following intravenous injection in mice. The regional distribution of this in vivo binding parallels the in vitro binding: heart and kidney were more labelled than brain. Benzodiazepine potencies in reducing [3H] RO5-4864 binding in vivo parallel relative affinities for [3H] RO5-4864 binding sites in isolated organs membranes: RO5-4864 greater than diazepam greater than clonazepam. PK 11195 a new compound, chemically unrelated to benzodiazepines, which is a potent inhibitor of [3H] RO5-4864 in vitro is also very effective (more than RO5-4864) after I.P. injection and oral administration. These results emphasize the feasibility of using this technique to examine the effects on various pharmacological and physiological manipulations of these binding sites in vivo. Moreover the fact that PK 11195 binds to these sites in vivo might indicate that this compound could help to elucidate the physiological relevance of the peripheral type of benzodiazepine binding sites.


Subject(s)
Isoquinolines/pharmacology , Receptors, Cell Surface/metabolism , Animals , Benzodiazepinones/metabolism , Brain/metabolism , Clonazepam/metabolism , Diazepam/metabolism , Isoquinolines/metabolism , Kidney/metabolism , Kinetics , Male , Mice , Myocardium/metabolism , Receptors, Cell Surface/drug effects , Receptors, GABA-A
17.
Life Sci ; 33(5): 449-57, 1983 Aug 01.
Article in English | MEDLINE | ID: mdl-6308375

ABSTRACT

The [3H]PK 11195, 1-(2-chlorophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinolinecarboxamide, binding sites in rat cardiac membranes are saturable, with high affinity, specific GABA-independent and correspond to the peripheral type of benzodiazepine. The order of potency of displacing agents was: PK 11195 greater than RO5-4864 greater than dipyridamole greater than diazepam greater than clonazepam. The Bmax obtained with [3H]PK 11195 was equivalent of the Bmax obtained with [3H]RO5-4864 in the same experimental conditions. However thermodynamic analysis indicates that the [3H]PK 11195 binding was entropy driven whereas the [3H]RO5-4864 binding was enthalpy driven. Consequently PK 11195 might be an antagonist of these binding sites and RO5-4864 an agonist or a partial agonist. The simultaneous use of both drugs might help to elucidate the physiological relevance of peripheral benzodiazepine binding sites.


Subject(s)
Benzodiazepinones/metabolism , Isoquinolines/metabolism , Receptors, Cell Surface/metabolism , Animals , Clonazepam/metabolism , Diazepam/metabolism , Dipyridamole/metabolism , Ligands , Male , Membranes/metabolism , Myocardium/metabolism , Rats , Receptors, GABA-A , Thermodynamics
18.
Life Sci ; 34(26): 2613-20, 1984 Jun 25.
Article in English | MEDLINE | ID: mdl-6330481

ABSTRACT

Two compounds with high affinity for the "peripheral type" benzodiazepine binding sites, PK 11195 (an isoquinoline derivative) and RO5-4864 (a benzodiazepine derivative) can modify the sensitivity of DBA/2J mice to audiogenic seizures. RO5-4864 (1-15 mg/kg) facilitates in a dose-dependent manner the audiogenic seizures and PK 11195 (2-5 mg/kg) antagonizes the RO5-4864 effects. At these doses PK 11195 alone does not modify the sensitivity to audiogenic seizures, but at doses between 20-80 mg/kg it protects DBA/2J mice against audiogenic seizures. By contrast PK 11195 is inactive against the facilitation of audiogenic seizures by ethyl-beta-carboline-3-carboxylate (a brain benzodiazepine receptor inverse agonist) and against the seizure elicited in absence of noise stimuli by RO5-4864 at doses between 20-40 mg/kg. These results suggest that facilitation by RO5-4864 of the audiogenic seizures and its antagonism by PK 11195 are mediated by the peripheral type benzodiazepine binding sites and agree with the thermodynamic analysis of the binding data which suggested that RO5-4864 might be an agonist and PK 11195 an antagonist. The good correlation between pharmacological effects and the occupancy degree of the binding sites as measured by the displacement of the "in vivo" [3H]-PK 11195 binding give an additional support to binding sites mediated effects.


Subject(s)
Benzodiazepinones/pharmacology , Isoquinolines/pharmacology , Receptors, Cell Surface/physiology , Seizures/physiopathology , Acoustic Stimulation , Animals , Benzodiazepinones/antagonists & inhibitors , Benzodiazepinones/metabolism , Convulsants , Dose-Response Relationship, Drug , Isoquinolines/metabolism , Male , Mice , Mice, Inbred DBA , Receptors, Cell Surface/drug effects , Receptors, GABA-A
19.
Life Sci ; 35(9): 953-62, 1984 Aug 27.
Article in English | MEDLINE | ID: mdl-6088933

ABSTRACT

RO5-4864 decreased in a dose-dependent manner, from 3 X 10(-9) M to 3 X 10(-6) M, the duration of intracellular action potential and the contractility in a guinea pig preparation. Diazepam was less effective and clonazepam inactive. The effects of RO5-4864 were GABA-independent and antagonized by PK 11195 but not by the selective antagonist of the brain type benzodiazepine receptors RO15-1788. These results show the pharmacological relevance of peripheral type benzodiazepine binding sites at the cardiac level.


Subject(s)
Benzodiazepinones/pharmacology , Convulsants/pharmacology , Isoquinolines/pharmacology , Myocardium/metabolism , Receptors, Cell Surface/metabolism , Action Potentials/drug effects , Animals , Clonazepam/pharmacology , Diazepam/pharmacology , Dose-Response Relationship, Drug , Electric Stimulation , Flumazenil , Guinea Pigs , Heart/drug effects , In Vitro Techniques , Myocardial Contraction/drug effects , Receptors, GABA-A
20.
Life Sci ; 35(12): 1249-56, 1984 Sep 17.
Article in English | MEDLINE | ID: mdl-6090832

ABSTRACT

[3H]PK 11195 binding to peripheral type benzodiazepine binding sites in kidney membranes is inhibited by the histidine blocking agent diethylpyrocarbonate. This reagent irreversibly decreases the Bmax for [3H]PK 11195 without affecting the affinity. By contrast binding of [3H]RO5-4864 is not affected by diethylpyrocarbonate treatment. However RO5-4864 can protect in a concentration dependent manner the [3H]PK 11195 binding site from diethylpyrocarbonate whereas clonazepam and RO15-1788 are not active. These results suggest that PK 11195 and RO5-4864 interact with different conformational states of the receptors that RO5-4864. This is in agreement with our previous hypothesis that PK 11195 is an antagonist and RO5-4864 an agonist at the "peripheral type" benzodiazepine receptors.


Subject(s)
Benzodiazepinones/metabolism , Diethyl Pyrocarbonate/pharmacology , Formates/pharmacology , Histidine/antagonists & inhibitors , Isoquinolines/metabolism , Kidney/metabolism , Receptors, GABA-A/metabolism , Animals , Cell Membrane/metabolism , Male , Rats , Rats, Inbred Strains , Receptors, GABA-A/drug effects
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