Antagonists Chlorpromazine Research Articles

The modulatory effects of biogenic amines on male mating performance in Bactrocera dorsalis.

In insects, the emergence of mating behavior requires the interplay among sex-determination hierarchy mechanisms that regulate sex-specific differentiation, perception and integration of different sensory cues, and precisely patterned behavioral outputs. Biogenic amines, including octopamine (OA), dopamine (DA), tyramine (TA), serotonin and histamine, have been identified and proposed as putative neurotransmitters, neurohormones and/or neuromodulators in the central nervous system of insects to influence multiple physiologies and behaviors. The current study provides the physiological roles and pharmacology of these biogenic amines in the mating performance of Bactrocera dorsalis. Silencing gene expressions coding for biosynthetic enzymes of DA and serotonin in male flies could decrease mating rates, while OA, TA and histamine had no such effects on mating. Furthermore, injection of DA or the DA receptor antagonist chlorpromazine could affect mating rate, as well as injection of serotonin. Pharmacological treatments with other biogenic amines or their receptor antagonists in male flies have no roles in regulating mating performance. We conclude that DA and its receptors are involved in regulating male mating behaviors in B. dorsalis, while changes in serotonin levels in male flies could also affect mating rates. In the current study, the modulatory effects of these biogenic amines on mating performance were investigated, and these results will be helpful in providing a new strategy for controlling B. dorsalis.

Dopamine relieves inflammatory responses through the D2 receptor after electroacupuncture at ST36 in a mouse model of chronic obstructive pulmonary disease.

To detect the role of dopamine in the anti-inflammatory effect of electroacupuncture (EA) at ST36 in a mouse model of chronic obstructive pulmonary disease (COPD). Twenty-eight male BALB/c mice were randomly divided into the control group, model group, sham EA (sham) group or ST36 EA (ST36) group in a 1:1:1:1 ratio (n = 7 each). The COPD mouse model was established through cigarette smoke (CS) exposure for 12 weeks. During the last 2 weeks, EA was applied at a sham point location or ST36 before CS exposure. Lung function, histopathological changes, inflammatory cell counts in bronchoalveolar lavage fluid (BALF), inflammatory cytokines in BALF, plasma, lung tissue homogenate (LTH), and plasma dopamine levels were detected in the different groups. Furthermore, the role of different dopamine receptors was explored through intraperitoneal injections of non-specific dopamine receptor antagonist chlorpromazine, specific dopamine D1 receptor antagonist SCH 23390 and specific dopamine D2 receptor antagonist eticlopride hydrochloride prior to ST36 EA and CS exposure. EA at ST36 improved lung function, alleviated lung and systemic inflammatory responses by reducing inflammatory cells and cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-8 and IL-1β in BALF, plasma and lung tissue in this COPD mouse model. Plasma dopamine was greatly increased after EA at ST36, negatively correlated with lung histological lesions and inflammatory cytokine levels, and positively correlated with mice body weight and lung function indicators. Chlorpromazine and eticlopride hydrochloride inhibited the anti-inflammatory effect of EA at ST36, while SCH 23390 showed no neutralizing effect. EA at ST36 could alleviate inflammation in this mouse model of COPD through the dopamine D2 receptor pathway.

Evidence for the Involvement of Dopamine in Ambulation Promoted by Menthol in Mice

The present study examines the mechanism that underlies the ability of menthol (ME), a major constituent of peppermint oil, to promote mouse ambulation. We initially confirmed that bupropion (BUP), a dopamine (DA) uptake inhibitor, promotes ambulation in ICR mice. Since the subcutaneous administration of ME produced similar effects in mice, we investigated the effects of ME on ambulation when combined with BUP. The results showed that BUP potentiated the effect of ME on mouse ambulation. We then examined effects of the DA antagonists chlorpromazine, haloperidol, fluphenazine, spiperone, and SCH12679 on the ability of BUP and ME to promote ambulation. All of these DA antagonists attenuated the effects of BUP and ME. Prior exposure to reserpine, which depletes monoamines, caused decreased sensitivity to the ability of BUP and of ME in promoting ambulation. The tyrosine hydroxylase inhibitor α-methyl-p-tyrosine, similarly decreased subsequent sensitivity to the effects of BUP and ME. These results suggest that DA is involved in the abilities of ME and BUP to promote ambulation in mice.

Calcium and Components of Lipid Signaling in Implementation of Hydrogen Sulfide Influence on the State of Stomata in Arabidopsis thaliana

A time and concentration dependence of the hydrogen sulfide donor sodium hydrosulfide (NaHS) influence on the state of stomata of Arabidopsis thaliana (Col-0) leaves, as well as the role of calcium and phospholipases in the implementation of its effects, was studied. Treatment of leaves with NaHS in the concentration range of 5–250 μM caused a decrease in the size of the stomatal aperture. The maximal effect of the stomatal closure was observed 90 min after the beginning of the treatment with H2S donor, and the stomatal aperture in NaHS variants was, on the contrary, much wider than in the control after 180 min of exposure. The effect of treatment with NaHS solutions on the stomata state was completely eliminated by hydroxylamine, the hydrogen sulfide scavenger, which indicates the specificity of NaHS effects as an H2S donor. The decrease in stomatal aperture and relative number of open stomata caused by the donor of hydrogen sulfide was almost completely leveled off by the pretreatment of leaves with the calcium channel blocker lanthanum chloride, the extracellular calcium chelator EGTA, the phospholipase C inhibitor neomycin, and the antagonist of the formation of cyclic adenosine-5'-diphosphate ribose—nicotinamide. In addition, the stomatal effect of theH2S donor was partially eliminated by the calmodulin antagonist chlorpromazine. The leveling of the hydrogen sulfide donor action on the state of stomatal apparatus of Arabidopsis leaves was also noted at the pretreatment of leaves with butanol-1, an inhibitor of phospholipase D-dependent formation of phosphatidic acid. A conclusion about the importance of calcium intake into the cytosol from various compartments, as well as lipid signaling mediators formed with the involvement of phospholipases C and D, in the implementation of hydrogen sulfide action on the state of stomata was made.

Endogenous hydrogen sulfide regulated by calcium is involved in thermotolerance in tobacco Nicotiana tabacum L. suspension cell cultures

Calcium (Ca2+)/calmodulin (CaM), a core component of calcium messenger system, is a multiple second messenger that is involved in multiple stress tolerance including heat tolerance in plants, hydrogen sulfide (H2S) is fast emerging similar functions, but Ca2+ and H2S crosstalk in the acquisition of thermotolerance is not completely understood. In this article, Ca2+ and CaM activated the activity of cysteine desulfhydrase (L-DES), followed by inducing endogenous H2S accumulation in tobacco suspension cultured cells, while treatment with Ca2+ chelator ethylene glycol-bis(b-aminoethylether)-N,N,N′,N′-tetraacetic acid and CaM antagonists chlorpromazine lowered L-DES activity and H2S accumulation. Interestingly, Ca2+- and CaM-activated L-DES activity and endogenous H2S accumulation were eliminated by H2S synthesis inhibitors DL-propargylglycine (PAG), aminooxy acetic acid (AOA), potassium pyruvate (PP) and hydroxylamine (HA), and the H2S scavenger hypotaurine (HT), indicating that Ca2+ and CaM regulated endogenous H2S generation via activating L-DES activity in tobacco cells. Furthermore, H2S donor NaHS, Ca2+ and CaM treatment alone significantly improved the thermotolerance of tobacco cells, and heat tolerance induced by Ca2+ and CaM was enhanced by exogenous NaHS, while weakened by PAG, AOA, PP, HA or HT. All above-mentioned results suggest that endogenous H2S generated by L-DES was involved, at least partly, in the thermotolerance induced by Ca2+ and CaM in tobacco suspension cell cultures.

The catecholamine stress hormones norepinephrine and dopamine increase the virulence of pathogenic Vibrio anguillarum and Vibrio campbellii.

Obtaining a better understanding of mechanisms involved in bacterial infections is of paramount importance for the development of novel agents to control disease caused by (antibiotic resistant) pathogens in aquaculture. In this study, we investigated the impact of catecholamine stress hormones on growth and virulence factor production of pathogenic vibrios (i.e. two Vibrio campbellii strains and two Vibrio anguillarum strains). Both norepinephrine and dopamine (at 100 μM) significantly induced growth in media containing serum. The compounds also increased swimming motility of the tested strains, whereas they had no effect on caseinase, chitinase, and hemolysin activities. Further, antagonists for eukaryotic catecholamine receptors were able to neutralize some of the effects of the catecholamines. Indeed, the dopaminergic receptor antagonist chlorpromazine neutralized the effect of dopamine, and the α-adrenergic receptor antagonists phentolamine and phenoxybenzamine neutralized the effect of norepinephrine, whereas the β-adrenergic receptor antagonist propranolol had limited to no effect. Finally, pretreatment of pathogenic V. campbellii with catecholamines significantly increased its virulence toward giant freshwater prawn larvae. However, the impact of catecholamine receptor antagonists on in vivo virulence was less clear-cut when compared to the in vitro experiments. In summary, our results show that—similar to enteric pathogens—catecholamines also increase the virulence of vibrios that are pathogenic to aquatic organisms by increasing motility and growth in media containing serum.

Effects of adrenoceptor compounds on larval metamorphosis of the mussel Mytilus coruscus

The metamorphosis responses of mussel (Mytilus coruscus) larvae to adrenoceptor compounds were investigated through a series of bioassays. The adrenergic agonist, epinephrine, as a positive control, exhibited significant inducing activity. Phenylephrine and clonidine induced larval metamorphosis at 10− 6 to 10− 4 M concentrations in both 24-h and continuous exposure assays. Dobutamine induced larval metamorphosis at 10− 5 M in the 24-h exposure assays, and the percentage of larval metamorphosis was very low (< 5%). Methoxyphenamine exhibited inducing activity at 10− 4 M in the continuous exposure assays, and the percentage of larval metamorphosis was 8%. No larval mortality was observed for these five agonists at all concentrations tested. Among these antagonists, α1-adrenergic receptor antagonist chlorpromazine and amitriptyline showed by far the most promising inhibiting effects, indicating that G-protein-coupled α1-adrenoceptors may be involved in the process of larval metamorphosis in M. coruscus. The α2-adrenergic receptor antagonist idazoxan also inhibited the larval metamorphosis of M. coruscus, indicating that larval metamorphosis may also be mediated by G-protein-coupled α2-adrenoceptors. Atenolol and butoxamine also inhibited larval metamorphosis induction by epinephrine. Thus, these adrenergic agonists can be used as non-toxic and promising inducers of larval metamorphosis in this species, and to improve M. coruscus larval production for aquaculture. The present study provides a novel insight into the mechanism modulating the metamorphosis of larvae of the mussel M. coruscus.

Role of Ca/CaN/NFAT signaling in IL-4 expression by splenic lymphocytes exposed to phthalate (2-ethylhexyl) ester in spleen lymphocytes

The aims of present study were to investigate the effect of phthalate (2-ethylhexyl) ester (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) on Th1/Th2 balance signaling for interleukin 4 (IL-4) expression in splenic lymphocytes, and contribution of MEHP to any hypothesized changes in vitro. Primary splenic lymphocytes were exposed to DEHP/MEHP. ELISA and Western blotting were used to detect proteins. Confocal-microscopy was used to examine nuclear translocation. Nuclear factor of activated T cells (NFAT) DNA binding activity was examined by electrophoretic mobility-shift assay. DEHP significantly increased IL-4 and interferon gamma (IFN-γ) level, and reduced Th1/Th2 ratio (reflected by IFN-γ/IL-4) with 5 μg/L Concanavalin A (ConA) treatment. While MEHP reduced Th1/Th2 ratio (represented by IFN-γ/IL-6). IL-4 mRNA was significantly increased by DEHP but not by MEHP after PMA and Ion treatment. DEHP significantly inhibited NFATp protein in cytosol and nucleus. DEHP augmented nuclear translocation of NFATc in transfected EL4 cells and NFAT DNA-binding activity. DEHP-mediated enhancement of calcium-dependent phosphatase calcineurin (CaN) protein, and NFAT and IL-4 expression were abrogated by calcium antagonist verapamil and CaN inhibitor tarcolimus. Ca(2+)/calmodulin antagonist chlorpromazine significantly suppressed IL-4 and CaN production with no NFAT mRNA change. Our study suggests that DEHP and MEHP impact Th1/Th2 balance by modulating different cytokines. DEHP-affected IL-4 expression through Ca/CaN/NFAT signaling pathway, but no effect was discovered for MEHP.

Constitutively active 5-HT2/α1 receptors facilitate muscle spasms after human spinal cord injury

In animals, the recovery of motoneuron excitability in the months following a complete spinal cord injury is mediated, in part, by increases in constitutive serotonin (5-HT2) and norepinephrine (α1) receptor activity, which facilitates the reactivation of calcium-mediated persistent inward currents (CaPICs) without the ligands serotonin and norepinephrine below the injury. In this study we sought evidence for a similar role of constitutive monoamine receptor activity in the development of spasticity in human spinal cord injury. In chronically injured participants with partially preserved sensory and motor function, the serotonin reuptake inhibitor citalopram facilitated long-lasting reflex responses (spasms) previously shown to be mediated by CaPICs, suggesting that in incomplete spinal cord injury, functional descending sources of monoamines are present to activate monoamine receptors below the lesion. However, in participants with motor or motor/sensory complete injuries, the inverse agonist cyproheptadine, which blocks both ligand and constitutive 5-HT2/α1 receptor activity, decreased long-lasting reflexes, whereas the neutral antagonist chlorpromazine, which only blocks ligand activation of these receptors, had no effect. When tested in noninjured control participants having functional descending sources of monoamines, chlorpromazine was effective in reducing CaPIC-mediated motor unit activity. On the basis of these combined results, it appears that in severe spinal cord injury, facilitation of persistent inward currents and muscle spasms is mainly mediated by the activation of constitutive 5-HT2 and α1 receptor activity. Drugs that more selectively block these constitutively active monoamine receptors may provide better oral control of spasticity, especially in motor complete spinal cord injury where reducing motoneuron excitability is the primary goal.

Involvement of calcium and calmodulin signaling in adaptation to heat stress-induced oxidative stress in Solanum lycopersicum L. leaves

Heat stress is a common form of stress suffered by plants. Therefore, plants have evolved mechanisms to cope with the problems caused by high temperatures. In this study, the involvement of calcium ion and calmodulin (Ca 2+ -CaM) in the protection against heat stress-induced oxidative damage in tomato ( Solanum lycopersicum L.) seedlings was investigated. Treatment of tomato leaves with short-term heat stress led to significant increase in the level of malondialdehyde (MDA) and protein oxidation (in terms of carbonyl groups), two important parameters of oxidative stress. However, such oxidative processes were mitigated by pretreatment with Ca 2+ and aggravated by pretreatment with the Ca 2+ chelator ethylene glycol-bis(β-amino ethyl ether)-N,N,N’,N’-tetraacetid acid (EGTA), the Ca 2+ channel blockers lanthanum chloride (LaCl 3 ), or the CaM antagonists chlorpromazine (CPZ), trifluoperazine (TFP) and N-(6-aminohexyl)-5-chloro-1-naphthalenesul-fonamide (W7). Besides, Ca 2+ pretreatment significantly reduced the accumulation of reactive oxygen species (ROS), O 2 .- and H 2 O 2 and remarkably induced the total activities of the antioxidant enzymes superoxide dismutase (SOD) and ascorbate peroxidase (APX) under heat stress, while EGTA, LaCl 3 , CPZ, TFP and W7 pretreatment reversed them. The results obtained here suggest that Ca 2+ -CaM signaling pathways are involved in resistance to heat stress-induced oxidative stress by regulation of antioxidant mechanisms in tomato leaves. Key words: Calcium, calmodulin, heat stress, oxidative stress, Solanum lycopersicum L.

Interaction between Dopaminergic and Angiotensinergic Systems on Thirst in Adult Male Rats

Thirst, which provides the motivation to drink, is an important component of the coordinated sequence of physiological responses that maintain the volume and composition of body fluids. Special structures in the central nervous system like periventricular organs detect changes in these parameters continuously. The present study investigated the interaction between dopaminergic and angiotensinergic systems on water intake in adult male rats. Intracerebroventricular (ICV) injections were carried out in all experiments after 24 h deprivation of water intake. After the deprivation interval, the volume of consumed water was measured for 1h. Administration the angiotensinergic (AT1) receptor antagonist Losartan (45 μg/rat), and the dopaminergic antagonist Chlorpromazine (40 μg/rat) significantly decreased water intake when compared to saline-treated controls. In contrast, ICV microinjection of the dopaminergic agonist Bromocriptine (10 μg/rat) significantly increased water intake when compared to saline-treated controls. ICV injection of Bromocriptine 15min after Losartan administration was able to attenuate the inhibitory effect of Losartan on water intake, whereas administration of Chlorpromazine 15 min after Losartan was unable to change the Losartan effect. These results suggest that the dopaminergic system interactions with the angiotensinergic system to regulate water intake through circumventricular organs. Dopaminergic and angiotensinergic neurons can monitor and regulate water intake via the stimulatory and inhibitory effects on each other, respectively.

Hydrogen sulfide donor sodium hydrosulfide-induced heat tolerance in tobacco (Nicotiana tabacum L) suspension cultured cells and involvement of Ca2+ and calmodulin

Hydrogen sulfide (H2S) is considered as a new emerging cell signal in higher plants. Hydrogen sulfide donor, sodium hydrosulfide, pretreatment significantly increased survival percentage of tobacco suspension cultured cells under heat stress and regrowth ability after heat stress, and alleviated decrease in vitality of cells, increase in electrolyte leakage and accumulation of malondialdehyde (MDA). In addition, sodium hydrosulfide-induced heat tolerance was markedly strengthened by application of exogenous Ca2+ and its ionophore A23187, respectively, while this heat tolerance was weakened by addition of Ca2+ chelator ethylene glycol-bis(b-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA), plasma membrane channel blocker La3+, as well as calmodulin (CaM) antagonists chlorpromazine (CPZ) and trifluoperazine (TFP), respectively, but intracellular channel blocker ruthenium red (RR) did not. These results suggested that sodium hydrosulfide pretreatment could improve heat tolerance in tobacco suspension cultured cells and the acquisition of this heat tolerance requires the entry of extracellular Ca2+ into cells across the plasma membrane and the mediation of intracellular CaM.

Dopamine as an anorectic neuromodulator in the cockroachRhyparobia maderae

Insects, including cockroaches, self-select a balanced diet when faced with different nutrient choices. For self-selection to be carried out effectively, insects possess neuroregulatory systems to control their food intake. In the present study, we examined the role of the neurotransmitter dopamine (DA) in the feeding regulation of the Madeira cockroach (Rhyparobia maderae). When R. maderae nymphs were injected with 20 μl of 100 mmol l(-1) DA, they showed an 83.3% reduction in sucrose intake and a 78.9% reduction in total intake compared with saline-injected controls. The DA agonist, 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (6,7-ADTN) (100 mmol l(-1) in 1 μl), caused a significant reduction in sucrose feeding, reducing feeding by 47.3% compared with saline-injected controls. Protein feeding was also significantly reduced by 6,7-ADTN to 62%. Rhyparobia maderae nymphs injected with the DA antagonist chlorpromazine (100 mmol l(-1) in 1 μl) did not differ significantly from control nymphs in their feeding behavior. Interestingly, R. maderae nymphs injected with 2 μl or 5 μl chlorpromazine (100 mmol l(-1)) showed significantly increased mortality rates of 47.5% or 66.7%, respectively. The DA antagonist, spiperone (100 mmol l(-1) in 1 μl), caused a significant feeding response, showing an increase in feeding in both sucrose (310.6%) and total intake (236.3%). Casein feeding in R. maderae nymphs was also elevated (70.8%) but this was not statistically significant. The experiments with DA, the DA agonist 6,7-ADTN and the DA antagonist spiperone strongly suggest that the neurotransmitter DA is involved in regulating feeding in the cockroach R. maderae.

Atomic Force Microscopy Study of the Conformational Change in Immobilized Calmodulin

Maintaining the biological functionality of immobilized proteins is the key to the success of numerous protein-based biomedical devices. To that end, we studied the conformational change in calmodulin (CaM) immobilized on chemical patterns. 1-Cysteine-mutated calmodulin was immobilized on a mercapto-terminated surface through cysteine-Hg-mercapto coupling. Utilizing atomic force microscopy (AFM), the average height of immobilized calmodulin was determined to be 1.87 ± 0.19 nm. After incubation in EGTA solution, the average height of the protein changed to 2.26 ± 0.21 nm, indicating the conformational change of CaM to Apo-CaM. Immobilized CaM also demonstrated a conformational change upon the reaction with known calmodulin antagonist chlorpromazine (CPZ). After incubation in CPZ solution, the average height of CPZ-bound CaM increased to 2.32 ± 0.20 nm, demonstrating that immobilized CaM has a similar response to that in bulk solution. These results show that the immobilization of calmodulin on a solid support does not interfere with the ability of the protein to bind calcium and calmodulin antagonists. Our results demonstrate the feasibility of employing AFM to probe and understand protein conformational changes.

Evidence for dopamine involvement in ambulation promoted by pulegone in mice

I investigated whether dopamine (DA) is involved in the ambulation promoted by pulegone (PUL), a constituent of peppermint oil, in ICR mouse. Co-administration of PUL and bupropion (BUP) had an additive effect on their ambulation-promoting activities. When administered with PUL, the DA antagonists chlorpromazine, fluphenazine, haloperidol, SCH12679, and spiperone all attenuated the effect of PUL on ambulation. In addition, pretreatment with the DA depletor reserpine produced no subsequent sensitivity to the effect of PUL. Taken together, DA may be involved in the ability of PUL to promote ambulation in ICR mice but PUL may not be a direct DA agonist. The chemical structure of PUL is similar to menthol and menthone, and thus they may all be acting through a common mechanism.

Comparative pharmacology of two D1-like dopamine receptors cloned from the silkworm Bombyx mori

Dopamine (DA) is a physiologically important biogenic amine in insect peripheral and nervous tissues. We recently cloned two DA receptors (BmDopR1 and BmDopR2) from the silkworm Bombyx mori and identified them as D1-like receptors, which activate adenylate cyclase to increase intracellular cAMP levels. In this study, these two receptors were stably expressed in HEK-293 cells, and the dose-responsiveness to DA and their pharmacological properties were examined using cAMP assays. BmDopR1 showed a dose-dependent increase in cAMP levels at DA concentrations up to 10 −7 M with EC 50 of 3.30 nM, while BmDopR2 required 10 −6 M DA for activation. In BmDopR1-expressing cells, DA at 10 −6–10 −4 M induced 30–50% lower cAMP production than 10 −7 M DA. BmDopR2-expressing cells showed a standard sigmoidal dose–response, with maximum cAMP levels attained with 10 −5–10 −4 M DA and EC 50 of 1.30 μM. Both receptors had similar agonist profiles, and the typical vertebrate D1-like receptor agonist SKF-38393 was ineffective. Experiments with antagonists revealed that BmDopR1 exhibits D1-like features. However, the pharmacology of BmDopR2 was distinct from D1-like receptors; the typical vertebrate D1-like receptor antagonist SCH-23390 was less potent than the nonselective antagonist flupenthixol and the D2-like receptor antagonist chlorpromazine. The rank order of activities of several antagonists for BmDopR1 and BmDopR2 was more similar to that of Drosophila melanogaster DA receptors than Apis mellifera DA receptors. These data suggest that DA receptors could be potential targets for specific insecticides or insectistatics.

Modulatory role of dopamine D 2 receptors and fundamental role of L-type Ca 2+ channels in the induction of long-term potentiation in the basolateral amygdala-dentate gyrus pathway of anesthetized rats

We have previously found that the induction of long-term potentiation in the synaptic pathway from the basolateral amygdala to the dentate gyrus (BLA-DG LTP) is regulated by L-type Ca 2+ channels, dopamine D 2 receptors and GABAergic inhibition. In the present study, we investigated possible relations among the three mechanisms by using anesthetized rats. Blockade of GABAergic inhibition with picrotoxin abolished both the inhibitory effect of the dopamine D 2 receptor antagonist chlorpromazine and the promoting effect of the dopamine D 2 receptor agonist quinpirole on the induction of BLA-DG LTP. However, the inhibitory effect of the L-type Ca 2+ channel blocker verapamil on BLA-DG LTP was not affected by picrotoxin. These results suggest that the role of dopamine D 2 receptors in the induction of BLA-DG LTP is modulatory and depends on GABAergic inhibition, whereas the role of L-type Ca 2+ channels is fundamental.

Evidence for dopamine involvement in ambulation promoted by menthone in mice

The present study examines the mechanism that underlies the ability of menthone (MTN), a constituent of peppermint oil, to promote mouse ambulation. Since bupropion (BUP), a dopamine (DA) uptake inhibitor, promotes mouse ambulation, the effect of MTN combined with BUP on ambulation was investigated. The results showed that BUP with MTN produced an additive interaction on mouse ambulation. The effects of DA antagonists chlorpromazine, fluphenazine, haloperidol, SCH12679 and spiperone on the ability of MTN to promote ambulation were then examined. All of these antagonists attenuated the effects of MTN. Prior exposure to the tyrosine hydroxylase inhibitor α-methyl- p-tyrosine, which inhibits catecholamines synthesis, decreased subsequent sensitivity to the effect of MTN. These results suggest that DA is involved in the ability of MTN to promote ambulation in mice.

Ca2+‐Calmodulin is Involved in Betacyanin Accumulation Induced by Dark in C3 Halophyte Suaeda salsa

Abstract The C3 halophyte Suaeda salsa was used to investigate the roles of Ca2+, Ca2+ channels, and calmodulin (CaM) in betacyanin metabolism. Seeds of S. salsa were cultured in both the dark and light for 3 days. The fresh weight and betacyanin content were much higher in S. salsa seedlings formed in the dark than in seedlings formed in the light. The addition of Ca2+ to the half‐strength MS nutrient solution promoted betacyanin accumulation in the dark, whereas Ca2+ depletion by EGTA suppressed the dark‐induced betacyanin accumulation in shoots of S. salsa. The Ca2+ channel blocker LaCl3 also inhibited dark‐induced betacyanin accumulation. The highest activity of CaM and the maximum betacyanin content decreased by 51% and 45%, respectively, in shoots of S. salsa seedlings treated with the potent CaM antagonist chlorpromazine in the dark. Furthermore, the other CaM antagonist N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide (W‐7) also inhibited the activity of CaM and dark‐dependent betacyanin accumulation, whereas its less active structural analog N‐(6‐aminohexyl)‐1‐naphthalenesulfonamide (W‐5) had little effect on the responses to dark of S. salsa seedlings. These results suggest that Ca2+, Ca2+‐regulated ion channels, and CaM play an important role in dark‐induced betacyanin accumulation in the shoots of the C3 halophyte S. salsa.

Ca(2+) and calmodulin modulate DNA-binding activity of maize heat shock transcription factor in vitro.

DNA-binding activity of a maize heat shock transcription factor (HSF) was induced by heat shock of a whole cell extract at 44 degrees C. Addition of the calcium ion chelator EGTA reduced the binding of the HSF to heat shock element (HSE) in vitro. Re-addition of CaCl(2) to the sample pretreated with EGTA restored the ability of the HSF to bind to DNA. DNA-binding activity of the HSF was also induced by directly adding CaCl(2) to a whole cell extract at non-heat-shock temperature, but not by MgCl(2). During HS at 44 degrees C, calmodulin (CaM) antagonists chlorpromazine (CPZ) and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W7) inhibited DNA-binding activity of the HSF in a concentration-dependent manner, but N-(6-aminohexyl)-1-naphthalenesulfonamide (W5), an inactive structural analogue of W7, did not. Addition of antiserum specific to CaM reduced the binding of the HSF to HSE. Re-addition of CaM to the sample pretreated with antiserum could restore the binding activity of the HSF. DNA-binding activity of the HSF was promoted by directly adding CaM to a whole cell extract at 44 degrees C, but not by BSA. Moreover, at non-heat-shock temperature, DNA-binding activity of the HSF was also induced by directly adding CaM to a whole cell extract, but not by BSA. Our observations further confirm the role of Ca(2+) in activation of the HSF in plant and provide the first example of the role of CaM in regulation of DNA-binding activity of the HSF. These results suggest that Ca(2+) and CaM are involved in HSP gene expression likely through regulating the activity of the HSF.