Significance of Ca2+ influx Through CatSper Channels
The process of hypermotility and its relationship with CatSper channels has been previously analyzed. After Ca2+ is allowed to go down its concentration gradient and into the sperm cell, various physiological processes are seen to be activated (1). Thus, CatSper channels appear to have a crucial mission when it comes to spermatozoa normal functionality and different studies have provided further evidence. In CatSper -/- (mutant) sperm, motility was notably impaired when a computer assisted-program was performed (2). Moreover, it was shown that the CatSper-null sperm possessed a normal motility initially and it was indeed hypermotility the function that was missing (2). As mentioned, hypermotility allows for successful fertilization due to a more powerful sperm tail wave-like movements. When referring to a knockout studies of specific CatSper subunits, a study demonstrated how motility was impaired in CatSper 1 -/- spermatozoa when compared to its wild-type counterpart as low-angled and minimal amplitude were observed in the flagellum of the mutant (27). Also, analysis in a viscous medium showed the effects of CatSper2 as CatSper 2 -/- mice sperm demonstrated less motility than the wild-type sperm (12). The lack of in-vivo measurements presented in these experiments is a limitation and justifies the need for techniques that will allow for more accurate methods.
CatSper channels have also been shown to be crucial for the
Normally in a muscle cell or a neuron, the voltage-gated sodium channels are supposed to open and close. Primarily, when the ligand-gated sodium channels open, sodium ions flood into the cell. Since sodium ions have a positive charge, this causes the cell interior to become more positive, a term known as depolarization; as a result, voltage-gated sodium channels open, causing even more sodium ions to enter the cell. Meanwhile, the action potential continues to move down the cell, and voltage-gated potassium channels open to allow potassium ions out of the cell to escape the positive interior; this process, known
Studying these processes has contributed in understanding how the body communicates and works internally. Basic experiments have been done to illustrate these procedures as part of the biological curriculum. Such practical lessons are fundamental in learning biological sciences, which are significant in day-to-day life
The second experiment sought to determine whether calcium entry is via L-type calcium channels, therefore, verapamil (10-5 M) was used to block these channels. The tissue was then stimulated using 0.2ml of Ach (10-5 M) and K+-depolarising solution.
Calcium plays a very significant role in our bodies. Approximately 99 percent of the calcium in our bodies is stored in the teeth and bones. Calcium generates about two percent of our total body weight. Calcium is crucial in bone formation, keeping strong bones and teeth and is known for helping to prevent osteoporosis. Although calcium is mostly thought about in the bones and teeth, it also plays important roles throughout the body. The amount of calcium outside the bones and teeth may be small in comparison to what is inside the bones and teeth, but is very useful in many functions in the body. Calcium is required in functions such as the contraction
This experiment seeks to analyze how the resting membrane potential of Orconectes rusticus muscle cells changes in response to increasing [K+]o solution concentrations. By recording the intracellular voltage of the DEM, DEL1, and DEL2 crayfish muscle cells at six concentrations of [K+]o solution, we determined whether the observed resting membrane potentials (Vrest) were significantly different from the predicted Nernst equilibrium potential values. We hypothesized that the Vrest of the crayfish muscles at each concentration would not significantly differ from the Nernst potential, which solely considers the permeability of potassium ions to the cell membrane. However, our findings suggested differently, and results indicated that the Nernst equation did not accurately predict the obtained values of the resting membrane potential. The differences in muscle cell Vrest reveal instead that the membrane is differentially permeable to other ions.
Voltage gated channels are necessary components of life processes, in many organisms. One in particular, is the calcium voltage gated ion channel. Often lodged within the phospholipid bilayer, the imbalance of the calcium, or, the inside vs outside concentration, creates a gradient. The channel proteins often undergo conformations, states that which allow or block calcium ions from passing through. As ions move inside the cell, this creates a depolarization, or surge in the voltage. Clinically, this is associated with the heart and how it allows the heart to contract, which can be read in the
Semen is the male reproductive fluid, containing spermatozoa in suspension. Sperm is a male reproductive cell. Prostate is a gland surrounding the neck of the bladder in male mammals and releasing prostatic fluid. Urethra is a duct by which urine is convey out of the body from the bladder, and which in male vertebrates also conveys semen. Penis is the male genital organ of higher vertebrates, carrying the duct for the transfer of sperm during copulation. Glans is the head of a penis. A shaft is the cylindrical part of the penis between the scrotum and head. Seminiferous tubules is any of the numerous long convoluted tubules in the testis which are the sites where spermatozoa mature. Seminal vesicles is each of a pair of glands that open into the vas deferens near its junction with the urethra and secrete many of the components of semen. Bladder is a membranous sac in human and other animals, which urine is collected for excretion.
Performing reproductive research at Yale’s Dr. Jean-Ju Chung’s lab is my prominent after school commitment. At the Chung Lab, I investigate cellular signaling via ion channels, with a focus on mature spermatozoan motility. At the Lab, I study CatSper, a calcium channel of spermatozoa by learning new methods of experimentation and applying immunocytochemistry to label specific proteins.
Influx and efflux of calcium regulate the membrane potential of the cell, which in turn regulates the contractility of smooth muscle cells. However, we neglected to link calcium’s role in membrane potential to its effects on potassium channels, one of the focuses of the first paper and the main influence on vasodilation and constriction. Furthermore, although external sources backed up the influence of insulin in activating Ca2+-ATPase as we wrote in our second hypothesis, the new supporting information does not mention insulin while suggesting that glucose might have a role in be inhibiting these Ca+-dependent K+
The penis is the male organ through which sperm cells are transferred from the male to the female. The penis contains three columns of erectile tissue. Engorgement of this erectile tissue with blood causes the penis to enlarge and become firm this process is called erection. Two of the erectile columns form the dorsum and sides of the penis and are called the corpora cavernosa. The third column, the corpus spongiosum, forms the ventral portion of the penis. It expands to form a cap over the distal end of the penis. The spongy urethra passes through the corpus spongiosum, penetrates the glans penis, and opens as the external urethral orifice. At the base of
Hi I’m Calcium I have 20 protons, 20 electrons, and 20 neutrons. My atomic number is 20 and my atomic mass number is 40. My number of electrons in energy level is 20 and my energy level number is 20. Also the period number I belong in for the periodic table is 4. The discovery name is Humphry Davy and he was the one that made me. The year that I was discovered was 1808 and the country they decided to discover me was in England. My element symbol is Ca.
Calcium was discovered by Sir Humphry Davy at England in 1808. Calcium is a soft, gray metal. When it burns, it burns with a yellowish-red flame. When it is exposed to air, it develops a gray-white coating because it reacts with the oxygen in the air to form a coating of calcium oxide .Calcium comes from the Latin word calx meaning lime. Compounds such as lime were prepared by the Romans in the first century under the name calx. Literature dating back to about 975 AD notes that plaster of Paris is useful for setting broken bones. Other calcium compounds used in early times include limestone. Calcium metal was not isolated until 1808. After learning that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, Sir Humphry
Ion channel activity in mouse bone marrow-derived DCs was analyzed utilizing whole cell patch-clamp experiments. As shown in Fig. 1, DCs express Kv channels. They presumably belong to Kv1.3 and Kv1.5 families (45, 56, 66). Pretreatment of the cells with rapamycin was followed by a gradual decline of Kv channel activity, an effect becoming significant with 50 nM rapamycin and 6 h of incubation (Fig. 1, C and D).
The Navarrete et al. 2016 paper on in vitro fertilization revolved around attempts to determine whether transient exposure to a calcium ionphore alone was sufficient to overcome upstream hyperpolarization and PKA pathway defects in infertile mouse models that normally occur prior to an intracellular calcium increase in functional and sufficiently capacitated mouse sperm cells. Additionally, researchers examined Catsper knockout mice to determine if a transient calcium increase in these mice was also sufficient to overcome capacitation and fertility defects discovered in early experiments by Ren, D. et al. in 2001. Overall then the hypothesis of the paper would read something similar to: if a transient increase in calcium levels is sufficient to overcome defects in PKA pathways, Catsper calcium channel genes, or membrane hyperpolarization pathways in mouse sperm cells, then these mouse models when introduced to a calcium ionophore for a short period of time will exhibit increased rates of capacitation and fertilization. However, since the exposure must be transient in nature, those mice with inactive PMCA4 calcium efflux channels will remain infertile even when only exposed to a calcium ionophore for a short period of time. Figure one contains experimentally derived results demonstrating hyperactivation, fertilization rate, and blastocyst formation between two different mouse strains, as well as a western blot used to indicate the presence or absence of PKA pathway