3H-spiperone Binding Research Articles

Withdrawal from repeated morphine sensitizes mice to the striatal dopamine release enhancing effect of acute morphine.

The effects of morphine withdrawal and challenge on the alpha-methyl-rho-tyrosine (alpha MT)-induced depletion of dopamine (DA) as well as on DA metabolism and 3H-SCH 23390 and 3H-spiperone binding were studied in the striata of male mice. Morphine was given s.c. 3 times daily for 5 days followed by 1 to 3 days' withdrawal. The alpha MT-induced DA depletion was retarded in mice withdrawn for 1 day from repeated morphine. At this time point the striatal concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) fell, too. In mice withdrawn for 3 days from morphine neither DA depletion nor DOPAC or HVA concentrations differed from those of control mice. In control mice acute morphine challenge accelerated the DA depletion at the dose 10 mg/kg but not at the dose 30 mg/kg. Both doses elevated striatal DOPAC and HVA. In mice withdrawn from repeated morphine for 1 day acute morphine partially counteracted the withdrawal-induced retardation of DA depletion and elevated striatal DOPAC and HVA clearly less than in control mice. However, in mice withdrawn for 3 days 10 mg/kg of morphine clearly enhanced DA depletion and its effect on striatal HVA was significantly augmented. In these mice as in controls the 30 mg/kg dose did not alter striatal DA depletion and elevated HVA less than in controls. Acute morphine did not alter striatal 3-methoxytyramine (3-MT) concentration in control mice but at the dose 10 mg/kg increased it in mice withdrawn for 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of deltamethrin on regional brain polyamines and behaviour in young rats.

The present study examines the mechanism of neurotoxic action of a synthetic pyrethroid formulation deltamethrin in young rats. Newly weaned Wistar Albino male rats received deltamethrin of technical grade at a dose of 7.0 mg/kg body weight/day in corn oil, orally from postnatal day 22 to postnatal day 37. Deltamethrin significantly decreased the wet weight of the hippocampus without much affecting the weight of cerebellum, pons medulla, hypothalamus, frontal cortex and corpus striatum in comparison to respective controls. A significant increase in the activities of mitochondrial monoamine oxidase and microsomal acetylcholinesterase without any effect on microsomal Na+, K(+)-ATPase activity was observed in the brain of experimental animals. Our results further indicate that deltamethrin markedly impaired learning function and significantly increased the spontaneous locomotor activity while aggressive behaviour remained unaffected. An overall enhancement of polyamine levels in hypothalamus and corpus striatum accompanied with an overall decline in pon medulla and cerebellum was also noted. Maximum decrease of spermine and spermidine was registered in hippocampus, while these polyamines showed an increase in frontal cortex. In striatal membranes the binding of 3H-spiperone decreased and 3H-quinuclidinyl benzilate was elevated significantly. Deltamethrin-induced deviations in regional brain polyamine levels may be a possible cause for altered pathophysiology of the neurone.

An analog of MIF, alaptide: effect on serum prolactin, dopamine receptors and growth of rat adenohypophysis.

Alaptide is a drug chemically derived from prolyl-leucyl-glycin amide (PLG) which is effective after oral administration. We studied the effect of long term treatment with alaptide and estradiol-benzoate on serum prolactin, growth reactivity and dopamine DA-2 receptors in the anterior pituitary of male rats. Alaptide reduced adenohypophyseal weight when given alone, but only nonsignificantly reduced growth reactivity of the anterior pituitary (AP) raised by estradiol-benzoate (EB). Alaptide significantly decreased the serum level of prolactin but, on the other hand, significantly increased the binding of 3H-spiperone to dopamine DA-2 receptors in AP membrane preparations, without affecting affinity. The administration of alaptide plus EB together resulted in an additional increase of dopamine DA-2 binding sites. We assume that alaptide has a weak dopaminergic activity on the AP of male rats.

Down-regulation of beta-adrenergic and dopaminergic receptors induced by 2-phenylethylamine.

1. The effects of chronic administration (28 days s.c. via Alzet osmotic minipumps) of 2-phenylethylamine.HCl (10 mg kg-1 per day) and/or (-)-deprenyl.HCl (1 mg kg-1 per day) on dopamine and noradrenaline receptor subtypes have been measured in rat brain. 3H-CGP 12177 was used to label beta-adrenoceptors; 3H-spiperone and 3H-SCH 23390 were used to label D2-like and D1-like receptors. 2. Total cortical beta-adrenoceptor density was reduced by (-)-deprenyl but not 2-phenylethylamine alone. Combined administration of 2-phenylethylamine and (-)-deprenyl resulted in a significantly larger decrease than (-)-deprenyl alone. Subtype density analysis by competition experiments with ICI 89406 revealed that the (-)-deprenyl effect in cortex was due to a decrease in beta 1-adrenoceptor density. The combination of 2-phenylethylamine and (-)-deprenyl resulted in a significant decrease in both cortical beta 1- and cortical beta 2-adrenoceptors. Cerebellar beta-adrenoceptor density was not altered by the present drug treatments. The Kd values for total beta-adrenoceptor densities and Ki values for beta-adrenoceptor subtype densities were not altered by drug treatment in either cortex or cerebellum. 3. Administration of 2-phenylethylamine and of (-)-deprenyl resulted in a decrease in the density of D1-like 3H-SCH 23390 but not D2-like 3H-spiperone binding to dopamine receptors in the striatum. The effects of combined 2-phenylethylamine and (-)-deprenyl treatment on 3H-SCH 23390 binding were additive. These drug treatments did not alter Kd values for these binding sites. 4. The down-regulation of catecholamine receptors following chronically increased availability of 2-phenylethylamine may be due to the catecholamine releasing or uptake blocking effects of this amine. These effects may also be attributable to a direct neuromodulatory action of 2-phenylethylamine on catecholamine receptors. 5. The parallels between effects of increased 2-phenylethylamine availability and effects of administration of MAO inhibitor antidepressants on catecholamine receptor systems indicate that this substrate for MAO may mediate some of the effects of MAO inhibitor antidepressants.

3H-spiperone binding capacity in mononuclear cells: A family study

1. 1. A family study was carried out using a putative biological vulnerability trait in families of schizophrenics and schizoaffective indexprobands to investigate, if the clinical phenotype and a biological marker for schizophrenia are cosegregating within families. 2. 2. The binding capacity of the dopamine antagonist spiperone to mononuclear cells was investigated in 21 indexprobands and a total of 147 first and second degree relatives. 3. 3. Increased binding capacity could be found in 17 indexprobands and in their affected relatives, independently from clinical diagnosis and in 22% of their normal relatives. 4. 4. No increased binding capacity was found in 4 indexprobands and in their affected relatives and not n any of the unaffected relatives. These results indicate, that increased spiperone binding may cosegregate with the risk for functional psychoses and that families, loaded with psychiatric disturbances may be distinguished on a biological basis.

Chronic Antagonist Treatment Does not Alter the Mode of Interaction of Dopamine with Rat Striatal Dopamine Receptors

Chronic treatment with the D1 and D2 dopamine receptor antagonists SCH 23390 (0.5 mg/kg) and haloperidol decanoate (25 mg/kg) caused an up-regulation in D1 and D2 receptor densities, respectively, with no change in KD. Dopamine (20 microM) interacted with both receptor subtypes in a mixed competitive/non-competitive manner, causing a reduction in ligand binding affinity and an apparent decrease in receptor density. In the presence of dopamine, both vehicle-treated and SCH 23390-treated striatal preparations showed a significant loss in affinity for 3H-SCH 23390 binding to D1 receptors and a decrease in D1 receptor density of approximately 26%. Similarly, dopamine caused a substantial loss in 3H-spiperone binding affinity to D2 receptors and a 46% decrease in Bmax in both vehicle-treated and haloperidol-treated membranes. Thus, receptor up-regulation does not appear to alter the mode of interaction of dopamine with rat striatal dopamine receptors.

Chronic dietary pergolide preserves nigrostriatal neuronal integrity in aged-Fischer-344 rats

Pergolide, a potent D 2 presynaptic agonist with postsynaptic D 2 agonist activity and some D 1 agonist activity was administered in the diet (0.5 mg/kg/day) of male Fischer 344 rats from age 3 to age 26 months. We hypothesized that the potent D 2 presynaptic activity would reduce the baseline release of dopamine (DA) and thereby slow the formation of toxic oxidative metabolites that lead to age-related deterioration of nigrostriatal DA neurons. Pair-fed rats served as controls. We observed age-related losses of fluorescent DA cell bodies in the substantia nigra pars compacta and of fluorescent DA terminals in the striatum; chronic pergolide administration prevented these losses. Pergolide administration also prevented the age-related diminution of DA fluorescence intensity in substantia nigra cell bodies. A large decline in 3H-DA uptake with age was partially prevented by pergolide administration. We found no age-related alteration in the concentration of DA in the striatum and pergolide did not alter this concentration. Pergolide treatment resulted in only minor alterations in striatal 3H-spiperone binding and no change in dendritic arborizations of either DA substantia nigra neurons or medium spiny striatal neurons. Pergolide administration also prevented an age-related decline in circulating FSH levels. The uptake data and quantitative morphological findings suggest that pergolide administration in the diet for 2 years exerts a protective effect on age-related deterioration of DA nigrostriatal neurons. This finding was consistent with clinical reports of a subset of patients with Parkinson's disease in whom long-term efficacy of pergolide therapy is observed.

The acute effect of sertindole on brain 5-HT2, D2 and alpha 1 receptors (ex vivo radioreceptor binding studies).

The ability of sertindole to influence the ex vivo binding of 3H-ketanserin, 3H-prazosin and 3H-spiperone to 5-HT2 receptors, alpha 1-adrenoceptors and DA D2 receptors, respectively, in rat brain has been studied after acute treatment. Sertindole is a potent, long acting compound which readily passes the blood-brain barrier. It dose-dependently binds to all three receptors types. In line with in vivo behavioural experiments sertindole has the most pronounced effect on 5-HT2 receptors, lower effect on alpha 1-adrenoceptors and the lowest effect on striatal D2 receptors.

Selective up-regulation of D-1 dopamine receptors following chronic administration of SCH 39166 in primates

Caudate, putamen and frontal cortex tissues were obtained from rhesus monkeys that had taken part in a toxicology study required by the Food and Drug Administration. These monkeys had received daily oral treatments of SCH 39166 at three different doses (3, 12 and 48 mg/kg) for three consecutive months. Plasma membranes from the caudate and putamen were analyzed for changes in D-1 and D-2 receptor affinity and number using saturation analyses of 3H-SCH 23390 and 3H-spiperone binding, respectively. Saturation studies were performed on membranes from the frontal cortex using 3H-ketanserin to determine if 5HT 2 receptor number or affinity were affected by chronic treatment with SCH 39166. Results indicate a significant, dose-dependent up-regulation of D-1 receptor number in both caudate and putamen, with no changes in either D-2 receptors in the striatal regions or 5HT 2 receptors in the frontal cortex. These data, therefore, indicate that SCH 39166 is a selective antagonist at D-1 receptors in the CNS of nonhuman primates.

3H-spiperone labels sigma receptors, not dopamine D2 receptors, in rat and human lymphocytes

3H-Spiperone binds to dopamine D2 receptors in striatum and, under the assumption that it labels the same receptors in lymphocytes, this binding site has been suggested as a biological marker for schizophrenia. Recent studies, however, have raised questions about the existence of dopamine receptor changes in drug-free schizophrenic patients, as well as on the presence and/or dopaminergic nature of lymphocytic 3H-spiperone bindin the present study we have conducted an investigation of the binding of 3H-spiperone to rat and human lymphocytes. We found that 3H-spiperone binds in a specific, saturable and reversible manner to a site in lymphocytes; however, its dissociation constant Kd (9 nM) is about 40-fold higher than in striatum. An extensive investigation of the 3H-spiperone sites indicated that their pharmacological profile was not that of a dopamine D2 site, but rather that of sigma receptors, a novel class of non-dopaminergic, non-opioid receptors which bind with high affinity antipsychotic drugs. Sigma receptors were also identified in lymphocytes using the specific ligand 3H-DTG (1,3-di-o-tolyl-guanidine), whose binding characteristics were comparable to those of sigma receptors in rat brain. Receptor density and the pharmacological profile of 3H-spiperone and 3H-DTG were similar. Both compounds also labelled a higher number of sites in B cells than in T cells and a good correlation was found between the lymphocytic binding of both ligands in a group of 58 people. These findings indicate that sigma receptors are present in lymphocytes and suggest that 3H-spiperone binding in these cells occurs to sigma sites and not to dopamine D2 sites.

Binding of 3H-spiperone to mononuclear cells of schizophrenics: relations to clinical variables and outcome

Binding of 3H-spiperone to mononuclear cells of schizophrenics: relations to clinical variables and outcome

High Affinity3H-spiperone Binding to Lymphocytes: Reality or Artefact?

High Affinity³H-spiperone Binding to Lymphocytes: Reality or Artefact?

Role of genotype in the adaptation of the brain dopamine system to stress

Behavioral and biochemical analysis of the effects of stress on brain dopamine (DA) functioning in two inbred strains of mice reveals opposite patterns of adaptation to chronic stress. Chronically stressed mice of the C57BL/6 (C57) strain are characterized by hypersensitive mesolimbic DA autoreceptors and by a dramatic increase of D1/D2 DA receptor ratio (possibly postsynaptic) in the nucleus accumbens septi (NAS) as revealed by in vivo binding of 3H-spiperone and 3H-SCH23390. Chronically stressed DBA/2 (DBA) mice present, on the contrary, hyposensitive DA autoreceptors and no changes in the D1/D2 DA receptors ratio in this brain area. The analysis of the behavioral responses of chronically stressed mice of the C57 strain to the mixed D1/D2 receptor agonist apomorphine, to the selective D2 agonist LY171555 and to the selective D1 agonist SKF 38393 suggest a close relationship between the behavioral alterations produced by chronic stress and the alterations of sensitivity of D2 pre- and postsynaptic receptors in the mesolimbic system. Furthermore, chronically stressed C57 mice present a marked decrease of spontaneous-climbing behavior which is not observed in the mice of the DBA strain and is dependent on the alteration of the biphasic evolution of this behavior during exposure to the test situation which, for these mice, represents a novel environment. Acute exposure to aversive environmental conditions induces a biphasic alteration of DA transmission (initial increase of DA release followed by a decrease under control levels) in the NAS.(ABSTRACT TRUNCATED AT 250 WORDS)

Migraine, Serum Serotonin and Platelet 5–HT2 Receptors

In spite of recent theories about the aetiopathogenesis of migraine, serotonin continues to play a central role, explaining the efficacy of almost all migraine prophylactic drugs. In migraineurs with and without aura we measured (by HPLC-EC) the serum serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels between as well as during headache attacks. Between attacks of migraine with aura and at the beginning of attacks of both types of migraine the serum 5-HT and 5-HIAA concentration was significantly increased. These results were corroborated by 3H-spiperone binding to platelet membranes: in migraineurs with aura in the attack-free interval, there was a significant decrease in its Bmax, which suggests down-regulation of 5-HT2 receptors. In conclusion, we have verified that migraine with aura differs biochemically from migraine without aura.

Nitric oxide-producing vasodilators and nitric oxide inhibit DNA synthesis in vascular smooth muscle cells

Alpha adrenoceptor subtypes have been investigated by radioligand binding study in guinea-pig stomach using 3H-prazosin and 3H-yohimbine. The specific 3H-prazosin binding to guinea-pig stomach was saturable and of high affinity (KD = 1.4 nM) with a Bmax of 33 fmol/mg protein. Specific 3H-yohimbine binding to the tissue was also saturable and of high affinity (KD = 25.5 nM) with a Bmax of 150 fmol/mg protein. Adrenergic drugs competed for 3H-prazosin binding in order of prazosin > phentolamine > methoxamine > norepinephrine > clonidine > epinephrine > yohimbine. These drugs competed for 3H-yohimbine binding in order of yohimbine > phentolamine > clonidine > epinephrine > norepinephrine > prazosin > methoxamine. We also examined whether dopamine receptors exist in guinea-pig stomach, using radioligand binding study. Specific binding of 3H-spiperone, 3H-apomorphine, 3H-dopamine and 3H-domperidone was not detectable in the stomach. Dopaminergic drugs such as dopamine, haloperidol, domperidone and sulpiride competed for 3H-prazosin binding in order of haloperidol > domperidone > dopamine > sulpiride. Metoclopramide, sulpiride and dopamine competed for 3H-yohimbine binding in order of metoclopramide > sulpiride > dopamine. These results suggest that guinea-pig stomach has alpha1 and alpha2 adrenoceptors and has no specific dopamine receptors. It is also suggested that some dopamine receptor antagonists such as domperidone, haloperidol, sulpiride and metoclopramide have antagonistic actions on alpha adrenoceptors.

Time‐related changes in serum perphenazine, striatal 3H‐spiperone binding and regional brain acid metabolites of dopamine and 5‐hydroxy‐tryptamine after a single dose of perphenazine

A single dose of perphenazine (5.0 mg/kg) was administered intraperitoneally to male Wistar rats. The time-related alterations in serum levels of perphenazine, striatal 3H-spiperone binding ex vivo and the regional brain metabolism of dopamine and 5-hydroxy-tryptamine were studied. Low serum levels of perphenazine were observed together with increased Kd of 3H-spiperone. No significant changes in Bmax were observed. Since Kd of 3H-spiperone binding peaked several hours after the maximal serum levels of perphenazine, perphenazine in serum appeared not to directly reflect the events at the receptor level. The concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxy, 4-hydroxyphenylacetic acid (HVA) in the striatum were increased after perphenazine. They were maximal 1-3 h after the drug administration and showed positive correlations (correlation coefficient 0.93 and 0.80, respectively) with the serum levels of perphenazine. Increased levels of HVA were also observed both in the olfactory tubercle and in the frontal cortex. However, in the olfactory tubercle, administration of perphenazine did not significantly increase the DOPAC concentrations. In the olfactory tubercle 5-hydroxyindoleacetic acid (5-HIAA) was decreased 1-24 h after administration of perphenazine. In the striatum and in the frontal cortex only slight changes in 5-HIAA were seen. Thus, in the olfactory tubercle 5-hydroxytryptaminergic mechanisms could modulate the dopaminergic neurotransmission.

Methodology of 3H-spiperone binding to lymphocytes

Alterations in lymphocyte binding capacity for the dopamine antagonist 3H-spiperone may be of great interest in psychiatric and neurological disorders: an increase in capacity noted in lymphocytes of schizophrenic patients and their families may well turn out to be a phenotypic vulnerability marker. Since the 3H-spiperone binding assay with lymphocytes does not fulfill common receptor-binding assay criteria and depends more on crucial analytical conditions, shortcomings in binding assay might possibly lead to irreproducible results. A detailed methodological description of the binding assay and subsequent calculations has therefore been given in this paper.

Effect of Amantadine on Prolactin Secretion, Pituitary DNA Synthesis and <sup>3</sup>H-Spiperone Binding in Male Estrogen-Treated Rats

Amantadine, a well-known antiviral agent, causing an increase in dopamine synthesis, release and the inhibition of re-uptake of noradrenaline and dopamine in central and peripheral catecholaminergic neurons, is successfully used in the treatment of Parkinson's disease. In the present paper, we have studied the effect of various doses of amantadine on in vivo prolactin secretion and the incorporation of 3H-thymidine and 3H-spiperone binding by the anterior pituitary gland of long-term diethylstilboestrol-treated male Wistar rats. Four weeks after a subcutaneous implantation of Silastic tubes containing 10 mg of diethylstilboestrol, a dramatic rise in serum prolactin levels was observed, accompanied by an increased uptake of 3H-thymidine by DNA anterior pituitary cells. Amantadine, given in the subcutaneous doses of 50, 5 and 0.5 mg/kg of body weight attenuated the stimulatory effect of stilboestrol on serum prolactin concentration in a dose-dependent fashion. On the other hand, the incorporation of 3H-thymidine into DNA pituitary cells in all the groups of amantadine-treated rats was only slightly suppressed. In an additional experiment, Scatchard analyses were performed on the in vitro 3H-spiperone binding kinetics in a dispersed anterior pituitary cell culture prepared from the pituitaries of 6-week diethylstilboestrol-treated rats. It has been found that amantadine injected in the dose of 5 mg/kg of body weight for 14 days induced a twofold decrease in the density of dopamine D2 binding sites (36.6 +/- 9.4 vs. 70.3 +/- 3.4 fmol/10(6) cells; p less than 0.02), while the apparent affinity of the receptors was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions of 7-[3-(4-[2,3-dimethylphenyl]piperazinyl)-propoxy]-2(1H)-quinolinone binding in rat striatum: effects of lesions.

7-[3-(4-[2,3-Dimethylphenyl]piperazinyl)propoxy]-2(1H)-quinolinone (OPC-4392), a presynaptic dopamine autoreceptor agonist and postsynaptic D-2 receptor antagonist (Yasuda et al., Life Sci. 42: 1941-1954, 1988), was studied for its binding characteristics at 3H-SCH 23390-labeled dopamine D-1 receptors and 3H-spiperone-labeled dopamine D-2 receptors in rat striatum. The binding affinity of OPC-4392 for 3H-spiperone-labeled D-2 receptors was 500 times higher than for 3H-SCH 23390-labeled D-1 receptors. 6-Hydroxydopamine lesions of striatum and high-frequency current lesions of medial forebrain bundle did not affect the competition of OPC-4392 for 3H-spiperone binding. Kainic acid lesions of striatum significantly changed the one-site model fit to a two-site model fit of the competition curve of OPC-4392 for 3H-spiperone binding, suggesting that OPC-4392 competed with 3H-spiperone binding differently for postsynaptic dopamine D-2 receptors and for presynaptic dopamine autoreceptors.

Remoxipride versus haloperidol in the treatment of acute schizophrenia: The incidence and severity of extrapyramidal symptoms

Rats were treated with haloperidol (1.5mg/kg/day) in their drinking water for 9 months, with or without a subsequent withdrawal period of 7–10 days. Compared with controls, spontaneous locomotion and apomorphine-induced stereotypy were reduced in rats maintained on haloperidol whereas both behaviours were increased after the withdrawal period. Maximum specific 3H-spiperone binding to striatal membrane preparations was increased (about 65%) in drug-treated rats with or without a withdrawal period. The dissociation constant for 3H-spiperone binding was significantly increased only in those rats maintained on haloperidol with no withdrawal period. The increase in maximum binding of 3H-spiperone was larger than that reported after less prolonged administration of neuroleptics. The size of the change should be taken into account in assessing the increased ligand binding reported in post-mortem brains of schizophrenics.