The character of the background spike activity of cortical neurons under the influence of psychotropic drugs]

A comparison was made on alert rabbits between the nature of spike activity of normal cortical neurones and of those after a two-week daily administration of neuroleptics, namely chlorpromazine, trifluoperazine and haloperidol in 1 and 5 mg/kg doses. The groups of neurones did not differ in the mean frequency of firing. However, the use of the main components method and of cluster analysis showed considerable differences between neuronal activity following the action of neuroleptics and that in control animals. The most common effect of neuroleptics consisted in a reduction of the number of low frequency neurones with burst discharges and small dispersion of distribution of interspike intervals. Trifluoperazine and especially haloperidol differed from chlorpromazine in that they brought about an appearance of cortical neurones for which the distribution of interspike intervals had an almost symmetrical form and a mode of 80--170 msec. After the action of haloperidol about a third of the neurones had a mode up to 10 msec. An assumption has been made that the major effect of trifluoperazine and haloperidol consists in an increase in the reverberative activity of the brain.     

Metabolic effects of trifluoperazine in the liver and the influence of calcium

The effects of trifluoperazine on hepatic cell metabolism were investigated using isolated perfused rat liver. The following effects of trifluoperazine were found: (1) trifluoperazine inhibited oxygen uptake, the site of action being the mitochondria. Half-maximal inhibition occurred at concentrations around 50 μM; with 100 μM trifluoperazine the effect was already maximal. When Ca²⁺ was withdrawn from the perfusion medium and the intracellular Ca²⁺ pools were exhausted, the inhibitory action on respiration was no longer observable. The rein-troduction of Ca²⁺ restored inhibition. (2) Glycogenolysis and glycolysis were not significantly affected during the infusion of trifluoperazine. After stopping trifluoperazine infusion, however, glycogenolysis (glucose release) experienced a transitory stimulation. (3) Gluconeogenesis from lactate as the carbon source was inhibited by trifluoperazine. This inhibition was approximately proportional to the inhibition of oxygen uptake. Withdrawal of Ca²⁺ diminished, but it did not eliminate, inhibition of gluconeogenesis. (4) Ketogenesis was also inhibited in parallel with the inhibition of oxygen uptake. Withdrawal of Ca²⁺ from the perfusion fluid also abolished this action. (5) The effects of trifluoperazine were reverted very slowly when its infusion was stopped. The recovery of oxygen uptake at 50 min after cessation of the infusion was only 30%. Uptake of the substance was very fast. Absence of Ca²⁺ did not affect uptake. It was concluded that inhibition of mitochondrial energy metabolism is one of the most prominent effects of trifluoperazine in the liver. The fact that this inhibition depends on Ca²⁺ is unique.     

On the activity of trifluoperazine and palmitoylcarnitine in mice: delayed hypersensitivity models

The effect of pre- and post-challenge treatments with trifluoperazine and palmitoylcarnitine, two protein kinase C (PKC) inhibitors characterised by their interaction with the phospholipid enzyme cofactor, on the inflammation caused by delayed hypersensitivity (DTH) to dinitrofluorobenzene (DNFB) and sheep red blood cells (SRBC) in mice is reported. The activity of dexamethasone and two immunosuppressors, azathioprine and methotrexate, is also evaluated. The effectiveness of pre-treatment with each of the test drugs diminished when the DNFB challenge dose increased, whereas trifluoperazine and azathioprine were more active when administered after the challenge at the high DNFB dose. Trifluoperazine, which is also a calmodulin-antagonist, was the more effective of the PKC inhibitors tested on DNFB-DTH (39% and 59% inhibition swelling 24 and 96 h after challenge, respectively). SRBC-DTH was sensitive only to the action of the drugs given after challenge. In this test, PKC inhibitors showed a moderate effect, in the same range as methotrexate, whereas dexamethasone suppressed the reaction. The ability of trifluoperazine in inhibiting cutaneous DTH reaction, depending on the treatment schedule and the hapten challenge dose, has been determined.     

Effect of trifluoperazine on DNA synthesis during liver regeneration

An intraperitoneal injection of the calcium-calmodulin blocker trifluoperazine into rats at 4 hr after a partial hepatectomy produced a strong inhibition of DNA synthesis observed at 24 hr after surgery; but when injection was administered at 20 hr after hepatectomy, it did not produce any effect on DNA replication. These observations indicate that trifluoperazine acted by blocking one or more events involved in triggering DNA replication but it did not affect on-going DNA synthesis. A more detailed study indicated that when trifluoperazine was injected at 4 hr after surgery, a 12 hr delay in the cytosolic calmodulin surge observed between 6 and 12 hr after partial hepatectomy (previous to initiation of DNA replication) and also in the starting of DNA synthesis was produced. These findings suggest that the pre-replicative surge of cytosolic calmodulin could be involved in triggering DNA synthesis observed after partial hepatectomy.     

Effect of Trifluoperazine On Dna Synthesis During Liver Regeneration

Abstract. An intraperitoneal injection of the calcium-calmodulin blocker trifluoperazine into rats at 4 hr after a partial hepatectomy produced a strong inhibition of DNA synthesis observed at 24 hr after surgery; but when injection was administered at 20 hr after hepatectomy, it did not produce any effect on DNA replication. These observations indicate that trifluoperazine acted by blocking one or more events involved in triggering DNA replication but it did not affect on-going DNA synthesis. A more detailed study indicated that when trifluoperazine was injected at 4 hr after surgery, a 12 hr delay in the cytosolic calmodulin surge observed between 6 and 12 hr after partial hepatectomy (previous to initiation of DNA replication) and also in the starting of DNA synthesis was produced. These findings suggest that the pre-replicative surge of cytosolic calmodulin could be involved in triggering DNA synthesis observed after partial hepatectomy.     

Trifluoperazine abolishes the actions of bradykinin on glucose 1,6-bisphosphate levels and on the activities of glucose 1,6-bisphosphatase, phosphofructokinase and phosphoglucomutase

Injection of trifluoperazine abolished the bradykinin-induced decrease in intracellular concentration of glucose 1,6-bisphosphate (Glc-1,6-P2) in rat tibialis anterior muscle and skin. These changes in Glc-1,6-P2 levels may be attributed to the changes in the activity of glucose 1,6-bisphosphatase (the enzyme that degrades Glc-1,6-P2), which was markedly enhanced by bradykinin and reversed by trifluoperazine. Concomitantly to the changes in Glc-1,6-P2, the potent activator of phosphofructokinase and phosphoglucomutase, the activities of these enzymes were reduced by bradykinin and restored by trifluoperazine. These findings suggest that trifluoperazine treatment may have a beneficial effect on the depressed glycolysis induced by bradykinin in tissue damage.     

Enhancement of chemiluminescence of the neutrophils by low concentrations of trifluoperazine

One to 10 μM trifluoperazine was found to potentiate luminol-dependent chemiluminescence of neutrophils induced by n-formyl-methionyl-leucylphenyalanine. It did not potentiate chemiluminescence induced by A23187 or by phobor myristate acetate. Low concentrations of another calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, an intracellular Ca⁺⁺ antagonist 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate, and a local anesthetic dibucaine, were found to possess similar activity. It is suggested that trifluoperazine potentiates chemiluminescence by acting on certain cellular processes that follow after stimulation by n-formyl-methionyl-leucylphenylalanine, but not by A23187 or by phorbor myristate acetate, and that this effect may be calmodulin-independent.     

Trifluoperazine inhibits thyrotropin-releasing hormone-stimulated TSH secretion

In previous work changes of the thyrotropic secretion after administration of some substances affecting the calcium content in the cytosol were demonstrated. The object of the present investigation was to assess the hormonal response to the administration of trifluoperazine, a psychopharmaceutical preparation, the main mechanism of its action being the inactivation of the cytosol receptor for the calcium signal - calmodulin. The poor utilization of intracellular calcium of the secretory cell is then the factor which inhibits secretion proper. The thyrotropic secretory reserve (delta TSH) was assessed in the same subjects before and after trifluoperazine administration by the TRH test as the difference of values at rest and TRH-stimulated TSH levels during the 20th, 30th, 40th and 60th minute following intravenous administration of 200 micrograms TRH. It was revealed that this calmodulin antagonist administered for one week in amounts of 6-12 mg per day by mouth significantly inhibits the secretory response of TSH to TRH in healthy subjects during the 20th and 40th min. (P less than 0.05). The reproducibility of the TRH test repeated in a group of subjects not treated with trifluoperazine, however, under equal conditions and after the same time intervals as in the experiment with trifluoperazine was very satisfactory and thus physiological inhibition caused by repeated TRH administration could be ruled out. The inhibition of the secretory TSH response to TRH can be therefore considered the consequence of the direct effect of trifluoperazine on the thyrotropic secretory mechanism. Trifluoperazine significantly reduced serum calcium levels and raised phosphate levels, while it did not affect the blood levels of magnesium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Calcium-dependent exocytosis in an in vitro secretory granule plasma membrane preparation from sea urchin eggs and the effects of some inhibitors of cytoskeletal function

Egg cortical granules remain attached to the egg plasma membrane when the egg is ruptured. We present evidence that demonstrates that, when the cytoplasmic face of the egg plasma membrane is exposed to micromolar calcium concentrations, an exocytosis of the cortical granules occurs which corresponds to the cortical granule exocytosis seen when the egg is fertilized. The calcium sensitivity of the preparation is decreased by an increase in magnesium concentration and increased by a decrease in magnesium concentration. Exocytosis is inhibited by trifluoperazine (half inhibition at 6 microM), a drug that inhibits the action of the calcium-dependent regulatory protein calmodulin. Colchicine, vinblastine, nocodazole, cytochalasin B, phalloidin, N-ethylmaleimide-modified myosin subfragment 1, and antibody to actin are without effect on this in vitro exocytosis at concentrations that far exceed those required to disrupt microtubules and microfilaments. Conditions are such that penetration to the exocytotic site is optimal. It is unlikely, therefore, that either actin or tubulin participate intimately in exocytosis. Our data also exclude on quantitative grounds several other mechanisms postulated to account for the fusion of the secretory granule with the plasma membrane.     

Effects of sodium azide and trifluoperazine on growth,development and monolayer cell differentiation inDictyostelium discoideum

The effects of sodium azide and trifluoperazine on growth, cAMP-chemotaxis, morphogenesis and cell differentiation in the slime mouldDictyostelium discoideum were examined. Growth rate of cells pretreated with low chemical concentrations was reduced directly after the treatment but was partially recovered within two to three hours. The levels of growth inhibition were directly proportional to the chemical concentrations. Low concentrations of trifluoperazine (1 μM) had no clear effect on the morphogenesis of the wild type strain HM27, but induced partial phenotype correction in the final fruiting body of the sporogenous mutant HM28. On the other hand, all relatively non toxic treatments with sodium azide had no effect on morphogenesis of both strains and on cell differentiation of the wild type strain HM27. Both trifluoperazine and sodium azide shifted cell differentiation of the sporogenous mutant HM28 in monolayers from spore- to stalk-pathway. Higher concentrations of both chemicals inhibited cell differentiation in all strains completely. The results indicated that these chemicals influenced the effects of the sporogenous locus which plays a role in the spore/stalk determination mechanism in the sporogenous mutant HM28.     

Propranolol, atenolol, and trifluoperazine reduce the spontaneous occurrence of meiotic diploid products in Saccharomyces cerevisiae.

The effect of atenolol, propranolol, trifluoperazine, and caffeine on the occurrence of meiotic diploid and disomic products in Saccharomyces cerevisiae was investigated. We demonstrated that atenolol, propranolol, and trifluoperazine reduce the occurrence of meiotic diploid products and that propranolol also slightly decreases the spontaneous frequency of disomics. On the other hand, caffeine appears to be a powerful inducer of diploid meiotic products, but also shows a lesser effect on disomic induction. Since spontaneous or caffeine-induced diploids arise from a failure of the second meiotic division, it appears that the target of these drugs is at the beginning of the second meiotic division. The only common effect of trifluoperazine and propranolol, mainly investigated in mammals, was an inhibition of calmodulin activity via direct interaction. We tend, therefore, to believe that calmodulin activity must be a crucial point for the second meiotic division to begin. The increased induction of diploids, due to caffeine, may be interpreted as a consequence of an increased cyclic AMP level.     

Stuttering—The Effect of Treatment with D-Amphetamine and a Tranquilizing Agent,Trifluoperazine; A Preliminary Report on an Uncontrolled Study

In an institution for the mentally retarded, an uncontrolled study was made on the effects of d-amphetamine, d-amphetamine followed by trifluoperazine, and of combined d-amphetamine and trifluoperazine on stuttering. Of 28 patients to whom d-amphetamine was given, 14 showed improvement after one month''s treatment. Eight more showed improvement when trifluoperazine was given for one month to those who did not improve on d-amphetamine. In many cases, improvement was sustained at least six months after treatment was discontinued.Treatment with d-amphetamine was apparently more effective in patients with functional than with organic retardation.     

The effect of trifluoperazine (Stellazine) on Hymenolepis diminuta in vitro

The influence of the phenothiazine trifluoperazine (Stellazine) on the rat tapeworm Hymenolepis diminuta was examined. The parasite was incubated in glucose-containing Krebs-Ringer media (pH 7.4) at 37 degrees C which included Ca2+ or EGTA and a range of trifluoperazine concentrations (0-2 mM). Release of soluble protein and lactate dehydrogenase activity were taken as measures of release of cytosolic components. The release of lactate dehydrogenase depended on drug concentration, maximum levels occurring at 2 mM trifluoperazine, this corresponded to 2% of the total lactate dehydrogenase present in the cestode. The effect of phenothiazines of differing lipophilicity were compared, and for trifluoperazine sulfoxide only minimal amounts of lactate dehydrogenase activity and protein were released. These values were similar to those obtained when H. diminuta was incubated in drug-free media. Our findings suggest that the integrity of the parasite is related to its calmodulin content. The potential cestocidal properties of trifluoperazine are considered.     

Ca2+-dependent protein phosphorylation and insulin release in intact hamster insulinoma cells. Inhibition by trifluoperazine

Ca2+-dependent protein phosphorylation was studied in intact hamster insulinoma cells. Depolarizing concentrations of potassium which stimulate Ca2+ uptake and insulin release by these cells also increased phosphorylation of one peptide, Mr = 60,000 (P60). This was demonstrated by incubating 32P-labeled insulinoma cells in media containing 50 mM K+ followed by analysis of the cellular proteins by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis and autoradiography. Potassium-induced phosphorylation of P60 was nearly half-maximal after 1 min and reached a plateau by 10 min. The enhanced 32P-labeling of P60 observed in the presence of 50 mM K+ was Ca2+-dependent since omission of extracellular Ca2+ or addition of the Ca2+ channel blocker alpha-isopropyl-alpha-[(N-methyl-N-homoveratryl)-gamma-aminopropyl]3,4,5-trimethoxyphenylacetonitrile hydrochloride prevented the effect. Glucagon (3 microM), which stimulates insulin release in a cAMP-dependent manner, had no effect on P60 phosphorylation. A possible involvement of calmodulin was explored in studies using trifluoperazine. The Ca2+-dependent increase in phosphorylation of P60 was prevented by trifluoperazine. Moreover, Ca2+ influx-mediated insulin release and P60 phosphorylation were inhibited at nearly identical concentrations of trifluoperazine. Half-maximal inhibition of potassium-induced insulin release and P60 phosphorylation was seen at 2.6 microM and 2.5 microM trifluoperazine, respectively. The data are consistent with a sequence of events involving Ca2+ influx, phosphorylation of P60 by a calmodulin-dependent protein kinase, and resultant insulin secretion.     

Trifluoperazine Inhibits 45Ca2+ Uptake and Catecholamine Secretion and Synthesis in Adrenal Medullary Cells

Abstract: In isolated adrenal medullary cells, carbamyl-choline and high K⁺ cause the calcium-dependent secretion of catecholamines with a simultaneous increase in the synthesis of ¹⁴C-catecholamines from [¹⁴C]tyrosine. In these cells, trifluoperazine, a selective antagonist of calmodulin, inhibited both the secretion and synthesis of catecholamines. The stimulatory effect of carbamyl-choline was inhibited to a greater extent than that of high K⁺. The inhibitory effect of trifluoperazine on carbamylcholine-evoked secretion of catecholamines was not overcome by an increase in either carbamylcholine or calcium concentration, showing that inhibition by trifluoperazine occurs by a mechanism distinct from competitive antagonism at the cholinergic receptor and from direct inactivation of calcium channels. Doses of trifluoperazine that inhibited catecholamine secretion and synthesis also inhibited the uptake of radioactive calcium by the cells. These results suggest that trifluoperazine inhibits the secretion and synthesis of catecholamines mainly due to its inhibition of calcium uptake. Trifluoperazine seems to inhibit calcium uptake by uncoupling the linkage between cholinergic receptor stimulation and calcium channel activation.     

Role of allopurinol, verapamil, dexamethasone and trifluoperazine as prophylactic agents in intestinal ischemia-reperfusion

OBJECTIVE: To study the effect of prophylactic agents allopurinol, verapamil, dexamethasone and trifluoperazine on ischemic intestinal damage. STUDY DESIGN: Sixty albino Wistar rats weighing 120-150 g were used. Group 1 animals underwent sham laparotomy without ischemia-reperfusion injury. Group 2 animals underwent laparotomy and occlusion of superior mesenteric arteries for 30 minutes followed by 20 minutes of reperfusion without pretreatment. The allopurinol group received 50 mg/kg/day allopurinol intraperitoneally 2 days before ischemia-reperfusion injury. The verapamil group was given 0.3 mg/kg verapamil intravenously 5 minutes before laparotomy. The dexamethasone group was given 1.5 mg/kg dexamethasone intraperitoneally before laparotomy. The trifluoperazine group was given 10 mg/kg trifluoperazine intraperitoneally 6 hours before laparotomy. RESULTS: In the allopurinol group, generally the mucosa and villar structure were protected. In the verapamil group, shedding of cells at the tip of the villi is apparent. In the dexamethasone group, desquamation of the villar apex was seen. In the trifluoperazine group, edema and necrosis were seen in the mucosa. In statistical analysis of the MDA level, data were obtained after a respective measurement in all groups. CONCLUSION: In this study histopathologic results with agents that are effective on preventing the neutrophyle functions are mostly achieved.     

The effect of trifluoperazine on maturation of Xenopus laevis oocytes

Full grown Xenopus oocytes were incubated with trifluoperazine (TFP) or injected with TFP. Incubation of oocytes in TFP resulted in normal-appearing meiotic maturation, as judged by the presence of the white spot and the absence of the germinal vesicle. Cortical granule breakdown in TFP-incubated oocytes was not normal. Abnormal cortical granule breakdown was also observed when progesterone-maturated oocytes were activated in the presence of TFP. Oocytes microinjected with TFP and incubated with progesterone appeared to mature in a normal manner, as judged by the absence of the germinal vesicle; these underwent cortical granule breakdown following activation, but frequently lacked the white spot. Oocytes microinjected with TFP did not mature in the absence of progesterone. We conclude that incubation, although not microinjection, of oocytes with TFP induces essentially normal resumption of meiotic maturation.     

Specificity of the binding of trifluoperazine to the calcium-dependent activator of phosphodiesterase and to a series of other calcium-binding proteins.

Trifluoperazine inhibits the activation of phosphodiesterase by binding to the calcium-dependent activator. To determine further the specificity by which trifluoperazine binds to activator, we compared the binding of trifluoperazine to activator prepared from several species and tissues and to a number of other calcium-binding proteins devoid of activator activity. Trifluoperazine binds to activator prepared from human, bovine, rat and rabbit brain and from chick embryo fibroblasts. In each case, the binding of trifluoperazine to activator was qualitatively similar and related quantitatively to the ability of the preparation to activate phosphodiesterase. Of the other calcium-binding proteins examined, namely, troponin-C, S-100 protein, phospholipase A, phospholipase B and myosin light chain, only troponin-C displayed any significant calcium-specific binding of trifluoperazine. The binding to troponin-C, however, appeared to be different from the binding to activator; whereas the binding of trifluoperazine to actovator showed no cooperativity, the binding to troponin-C showed positive cooperatively. These results and earlier data showing that trifluoperazine fails to bind to a variety of other proteins, indicate that the binding of trifluoperazine to the calcium-dependent activator of phosphodiesterase is selective and suggest that this binding may explain some of the biochemical and pharmacological actions of this antipsychotic agent.     

Specificity of the binding of trifluoperazine to the calcium-dependent activator of phosphodiesterase and to a series of other calcium-binding proteins

Trifluoperazine inhibits the activation of phosphodiesterase by binding to the calcium-dependent activator. To determine further the specificity by which trifluoperazine binds to activator, we compared the binding of trifluoperazine to activator prepared from several species and tissues and to a number of other calcium-binding proteins devoid of activator activity.Trifluoperazine binds to activator prepared from human, bovine, rat and rabbit brain and from chick embryo fibroblasts. In each case, the binding of trifluoperazine to activator was qualitatively similar and related quantitatively to the ability of the preparation to activate phosphodiesterase.Of the other calcium-binding proteins examined, namely, troponin-C, S-100 protein, phospholipase A, phospholipase B and myosin light chain, only troponin-C displayed any significant calcium-specific binding of trifluoperazine. The binding to troponin-C, however, appeared to be different from the binding to activator; whereas the binding of trifluoperazine to actovator showed no cooperativity, the binding to troponin-C showed positive cooperatively.These results and earlier data showing that trifluoperazine fails to bind to a variety of other proteins, indicate that the binding of trifluoperazine to the calcium-dependent activator of phosphodiesterase is selective and suggest that this binding may explain some of the biochemical and pharmacological actions of this antipsychotic agent.     

Effects of calcium ionophore A23187 and calcium antagonists on 32Pi incorporation into polyphosphoinositides of rat cortical synaptosomes

The role of Ca2+ on 32Pi incorporation into polyphosphoinositides (PPI) of rat cortical synaptosomes was studied. Stimulation of muscarinic receptor by carbachol (1 mM) resulted in a decrease in 32Pi incorporation into phosphatidylinositol-4,5-bisphophaphate (TPI) and phosphatidylinositol-4-phosphate (DPI), and an increase in 32Pi incorporation into phosphatidylinositol (PI) and phosphatidic acid (PA), whereas no significant effect on other membrane phospholipids was found. This response could be blocked by atropine (1 microM). The stimulatory effect of carbachol required Ca2+ in the medium; the presence of 0.5 mM EGTA blocked the effect of carbachol on PPI turnover completely. Calcium ionophore A23187, at 1 microM, had a similar effect on PPI turnover by carbachol (1 mM). At higher concentrations (10-100 microM) of A23187, the PPI turnover rate was much enhanced. Depolarization of the membrane by high potassium (60 mM) in the presence of calcium resulted in an enhanced PPI turnover, which was similar to the results of the carbachol (1 mM) effect but to a lesser extent. Calcium antagonists, diltiazem and trifluoperazine, at 10 microM could block the carbachol effect on 32Pi incorporation into PPI in this preparation. Our results suggest that the enhancement of PPI turnover in rat cortical synaptosomes by carbachol, calcium ionophore or high potassium requires Ca2+, and it can be blocked by compounds which interfere with the availability of this ion, such as EGTA or calcium antagonists.