Manipulating external Ca2+ inhibits particle capture by planktotrophic echinoderm larvae

1990 ◽  
Vol 68 (12) ◽  
pp. 2610-2615 ◽  
Author(s):  
Michael W. Hart
Keyword(s):  
Calcium Ion ◽  
Channel Blocker ◽  
Artificial Seawater ◽  
Ciliated Cells ◽  
Particle Capture ◽  
Concentrated Solutions ◽  
Ciliary Reversal ◽  
Reversal Mechanism ◽  
Planktotrophic Larvae ◽  
Ciliary Beat

Planktotrophic larvae of echinoderms feed by filtering suspended particles from seawater using a ciliary reversal mechanism. The control of ciliary beat depends on calcium ion flux across the membranes of ciliated cells in many organisms. In an earlier study, T. H. J. Gilmour (1985. Can. J. Zool. 63: 1354–1359) observed that the calcium channel blocker verapamil failed to prevent particle capture by echinoid larvae, and he interpreted this result as indicating that ciliary reversals are not important in particle capture by these larvae. I have also found that echinoid and asteroid larvae feed normally (and have high rates of clearance) in concentrated solutions of verapamil in seawater, but particle captures by these larvae are qualitatively identical to those by the same larvae before exposure to verapamil and they appear to occur by ciliary reversal. Clearance rates are greatly depressed, however, for larvae in Ca2+-free artificial seawater and for larvae in artificial seawater containing 9 mM Co2+. Most particle captures under these conditions do not appear to occur by the reversal of ciliary beat. These observations suggest that verapamil fails to block calcium channels in the membranes of ciliated cells of echinoderm larvae, but that other methods of preventing transmembrane Ca2+ flux do interfere with ciliary reversals and particle capture.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

1,4-Dihydropyridine: A Dependable Heterocyclic Ring with the Promising and the Most Anticipable Therapeutic Effects

2019 ◽  
Vol 19 (15) ◽  
pp. 1219-1254 ◽  
Author(s):  
Abhinav Prasoon Mishra ◽  
Ankit Bajpai ◽  
Awani Kumar Rai
Keyword(s):  
Calcium Ion ◽  
Heterocyclic Compounds ◽  
Channel Blocker ◽  
Heterocyclic Ring ◽  
Therapeutic Effects ◽  
Voltage Gated ◽  
Therapeutic Benefits ◽  
Anti Cancer ◽  
Anti Oxidant ◽  
Synthetic Medicinal

: Nowadays, heterocyclic compounds act as a scaffold and are the backbone of medicinal chemistry. Among all of the heterocyclic scaffolds, 1,4-Dihydropyridine (1,4-DHP) is one of the most important heterocyclic rings that possess prominent therapeutic effects in a very versatile manner and plays an important role in synthetic, medicinal, and bioorganic chemistry. The main aim of the study is to review and encompass relevant studies related to 1,4-DHP and excellent therapeutic benefits of its derivatives. An extensive review of Pubmed-Medline, Embase and Lancet’s published articles was done to find all relevant studies on the activity of 1,4-DHP and its derivatives. 1,4-DHP is a potent Voltage-Gated Calcium Channel (VGCC) antagonist derivative which acts as an anti-hypertensive, anti- anginal, anti-tumor, anti-inflammatory, anti-tubercular, anti-cancer, anti-hyperplasia, anti-mutagenic, anti-dyslipidemic, and anti-ulcer agent. From the inferences of the study, it can be concluded that the basic nucleus, 1,4-DHP which is a voltage-gated calcium ion channel blocker, acts as a base for its derivatives that possess different important therapeutic effects. There is a need of further research of this basic nucleus as it is a multifunctional moiety, on which addition of different groups can yield a better drug for its other activities such as anti-convulsant, anti-oxidant, anti-mutagenic, and anti-microbial. This review would be significant for further researches in the development of several kinds of drugs by representing successful matrix for the medicinal agents.

scholarly journals The gravistimulation-induced very slow Ca2+ increase in Arabidopsis seedlings requires MCA1, a Ca2+-permeable mechanosensitive channel

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masataka Nakano ◽  
Takuya Furuichi ◽  
Masahiro Sokabe ◽  
Hidetoshi Iida ◽  
Hitoshi Tatsumi
Keyword(s):  
Calcium Ion ◽  
Channel Blocker ◽  
Upright Position ◽  
Ion Concentration ◽  
Early Event ◽  
Free Calcium ◽  
Permeable Channel ◽  
Mechanosensitive Ion Channel ◽  
And Function ◽  
Calcium Ion Concentration

AbstractGravity is a critical environmental factor affecting the morphology and function of plants on Earth. Gravistimulation triggered by changes in the gravity vector induces an increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) as an early process of gravity sensing; however, its role and molecular mechanism are still unclear. When seedlings of Arabidopsis thaliana expressing apoaequorin were rotated from the upright position to the upside-down position, a biphasic [Ca2+]c-increase composed of a fast-transient [Ca2+]c-increase followed by a slow [Ca2+]c-increase was observed. We find here a novel type [Ca2+]c-increase, designated a very slow [Ca2+]c-increase that is observed when the seedlings were rotated back to the upright position from the upside-down position. The very slow [Ca2+]c-increase was strongly attenuated in knockout seedlings defective in MCA1, a mechanosensitive Ca2+-permeable channel (MSCC), and was partially restored in MCA1-complemented seedlings. The mechanosensitive ion channel blocker, gadolinium, blocked the very slow [Ca2+]c-increase. This is the first report suggesting the possible involvement of MCA1 in an early event related to gravity sensing in Arabidopsis seedlings.

Control of the beat cycle of respiratory tract cilia by Ca2+ and cAMP

1992 ◽  
Vol 263 (2) ◽  
pp. L232-L242 ◽  
Author(s):  
A. B. Lansley ◽  
M. J. Sanderson ◽  
E. R. Dirksen
Keyword(s):  
Respiratory Tract ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Ciliated Cells ◽  
Intact Cells ◽  
Permeabilized Cells ◽  
Whole Cells ◽  
Phase Reduction ◽  
Before And After ◽  
Ciliary Beat

Beat frequency and the duration of the constituent recovery, effective, and rest phases of the beat cycle of respiratory tract cilia were measured photoelectronically before and after manipulation with ionomycin or isoproterenol. Both ionomycin, acting by increasing intracellular Ca2+, and isoproterenol, acting by elevating intracellular adenosine 3',5'-cyclic monophosphate (cAMP), increased beat frequency by reducing the duration of the three phases of the ciliary beat cycle in a similar manner. The addition of increasing concentrations of ATP to ciliated cells permeabilized by exposure to saponin caused a pattern of phase reduction indistinguishable from that observed in whole cells. The beat frequency of permeabilized cells was slower than that of whole cells and insensitive to changes in Ca2+ and cAMP. Ca2+ and cAMP may regulate ciliary beat frequency by acting at a common site within intact cells, possibly regulating the rate at which the axoneme can use ATP or the availability of ATP to the axoneme.

Experience in Counting Ciliary Beat Frequency from Vital Cytologic Sampling

1989 ◽  
Vol 3 (3) ◽  
pp. 151-154
Author(s):  
T. Deitmer ◽  
S. Phadhana-anek
Keyword(s):  
Functional State ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Time Shift ◽  
Ciliated Cells ◽  
Good Picture ◽  
Brush Biopsy ◽  
Epithelial Cell Layer ◽  
Sampling Procedures ◽  
Ciliary Beat

From a viable cytologic brush biopsy of the respiratory epithelium you can get an insight into the functional state of the epithelial cell layer, especially of the ciliated cells. We report on our experience of several hundred sampling procedures from the nasal and bronchial mucosa. The technique of the method is described, including the microphotometric apparatus to determine the ciliary beat frequency. We stress the importance of checking the ciliary beat frequency of the 10 most active cells of one preparation to get representative results. Futhermore it is decisive to watch them over a period of 10 seconds, considering the time shift of the ciliary beat frequency. Putting the cell solution into a counting chamber gives the possibility of differentiating viable and dead ciliated cells as well as squamous cells in the sample. These results proved to yield a good picture of the functional state of the sampled respiratory mucosal site.

scholarly journals Calcium Ion Channels: Roles in Infection and Sepsis Mechanisms of Calcium Channel Blocker Benefits in Immunocompromised Patients at Risk for Infection

2018 ◽  
Vol 19 (9) ◽  
pp. 2465 ◽  
Author(s):  
John D’Elia ◽  
Larry Weinrauch
Keyword(s):  
Vitamin D ◽  
Ion Channels ◽  
Inflammatory Response ◽  
Calcium Channel ◽  
Calcium Channel Blocker ◽  
Calcium Ion ◽  
Defense Mechanisms ◽  
Channel Blocker ◽  
Inadequate Response ◽  
Calcium Ion Channels

Immunosuppression may occur for a number of reasons related to an individual’s frailty, debility, disease or from therapeutic iatrogenic intervention or misadventure. A large percentage of morbidity and mortality in immunodeficient populations is related to an inadequate response to infectious agents with slow response to antibiotics, enhancements of antibiotic resistance in populations, and markedly increased prevalence of acute inflammatory response, septic and infection related death. Given known relationships between intracellular calcium ion concentrations and cytotoxicity and cellular death, we looked at currently available data linking blockade of calcium ion channels and potential decrease in expression of sepsis among immunosuppressed patients. Notable are relationships between calcium, calcium channel, vitamin D mechanisms associated with sepsis and demonstration of antibiotic-resistant pathogens that may utilize channels sensitive to calcium channel blocker. We note that sepsis shock syndrome represents loss of regulation of inflammatory response to infection and that vitamin D, parathyroid hormone, fibroblast growth factor, and klotho interact with sepsis defense mechanisms in which movement of calcium and phosphorus are part of the process. Given these observations we consider that further investigation of the effect of relatively inexpensive calcium channel blockade agents of infections in immunosuppressed populations might be worthwhile.

scholarly journals TNFαAffects Ciliary Beat Response to Increased Viscosity in Human Pediatric Airway Epithelium

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Claudia González ◽  
Karla Droguett ◽  
Mariana Rios ◽  
Noam A. Cohen ◽  
Manuel Villalón
Keyword(s):  
Airway Epithelium ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Ciliated Cells ◽  
Upper Airways ◽  
Pediatric Airway ◽  
Adenoid Tissue ◽  
Before And After ◽  
Autoregulatory Mechanism ◽  
Ciliary Beat

In airway epithelium, mucociliary clearance (MCC) velocity depends on the ciliary beat frequency (CBF), and it is affected by mucus viscoelastic properties. Local inflammation induces secretion of cytokines (TNFα) that can alter mucus viscosity; however airway ciliated cells have an autoregulatory mechanism to prevent the collapse of CBF in response to increase in mucus viscosity, mechanism that is associated with an increment in intracellular Ca+2level (Ca2+i). We studied the effect of TNFαon the autoregulatory mechanism that regulates CBF in response to increased viscosity using dextran solutions, in ciliated cells cultured from human pediatric epithelial adenoid tissue. Cultures were treated with TNFα, before and after the viscous load was changed. TNFαtreatment produced a significantly larger decrease in CBF in cultures exposed to dextran. Furthermore, an increment inCa2+iwas observed, which was significantly larger after TNFαtreatment. In conclusion, although TNFαhas deleterious effects on ciliated cells in response to maintaining CBF after increasing viscous loading, it has a positive effect, since increasingCa2+imay prevent the MCC collapse. These findings suggest that augmented levels of TNFαassociated with an inflammatory response of the nasopharyngeal epithelium may have dual effects that contribute to maintaining the effectiveness of MCC in the upper airways.

Pregnancy following discontinuation of a calcium channel blocker in the male partner

1995 ◽  
Vol 10 (3) ◽  
pp. 599-606 ◽  
Author(s):  
Avner Hershlag ◽  
George W. Cooper ◽  
Susan Benoff
Keyword(s):  
Ion Channel ◽  
Calcium Ion ◽  
Male Fertility ◽  
Channel Blocker ◽  
Male Partner ◽  
Channel Blockers ◽  
Ligand Receptors ◽  
Fertility Potential ◽  
Intra Uterine Insemination

Abstract The fertility potential of human sperm populations can be assessed by the presence of head-directed mannose ligand receptors (mannose-specific lectin) and the occurrence of spontaneous acrosome reactions after incubation under capacitating conditions in vitro. We have reported previously on the interaction between anti-hypertensive medications and their effects on these parameters of male fertility potential. In this report we document the effects of cessation of calcium ion channel blocker medication on male fertility. Motile spermatozoa from a 30 year old infertile patient on a calcium ion channel blocker as anti-hypertensive treatment had subnormal expression of mannose-specific lectin and did not exhibit spontaneous acrosome reactions. Three months following discontinuation of the medications, complete recovery of both the expression of head-directed mannose ligand receptors and the acrosome reaction was documented, though sperm motility and morphology remained unchanged. The couple had 2 years of infertility and previously failed to conceive through seven cycles of Pergonal/intra-uterine insemination. Conception occurred on the second Pergonal/intra-uterine insemination cycle after the husband discontinued calcium ion channel blocker medication. Calcium ion channel blockers may adversely affect sperm fertilizing potential. Discontinuation of such medications enhances the chances for conception.

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