Essay On Calcium Channels

From molecular perspective, hyperforin has multidirectional mechanisms of action. It acts on ligand-gated (GABA, NMDA and AMPA receptors) (29, 30) and voltage-gated channels (Ca2+, K+, and Na+) (29, 31). In contrast to blockade of ion transport through the plasma membrane, hyperforin can increased an inward Ca2+ current. These processes are dose dependent and probably involved a few different cellular events. In the details, hyperforin in in vitro studies increased the Ca2+ intracellular level by activation of the non-selective canonical transient receptor potential 6 channels (TRPC6) or by the releasing Ca2+ from mitochondria (32–34). As has been previously shown hyperforin activates intracellular

Exercise 1: Cell Transport Mechanisms and Permeability: Activity 5: Simulating Active Transport Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. The movement of sodium and potassium maintained by the Na+ -K+ pump You correctly answered: e. requires energy and is against a concentration gradient. 2. The sodium-potassium pump is classified as a(n) You correctly answered: a. antiporter. 3. The sodium-potassium pump moves _____ sodium ions and _____ potassium ions simultaneously. You correctly answered: b. 3, 2 4. Solutes that require active transport for movement might be too large to pass or might be You correctly answered: a. lipid insoluble.

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.

-If the potassium transport pump was blocked the leakage channels would still be open allowing Na+ to

Cystic fibrosis (CF) is a progressive condition in which epithelial exocrine glands are obstructed (Howe, 2001). Whilst many organs and bodily systems are disrupted by CF, the lungs and gastrointestinal organs are predominantly affected; it is also most common amongst the Caucasian population due to the autosomal recessive gene (Quitter et al., 2003 cited in Wolfe & Mash, 2006, pg 514). The faulty gene effects the production of cystic fibrosis transmembrane conductance regulator protein, which is responsible for the formation of molecular tunnels which monitor the movement of salts and water from the cells (Hopkin, 2010 pg 4).

Chloride channels are a structurally diverse superfamily of transmembrane proteins that facilitate the transport of negative anions across the cell membrane. These channels are involved in a plethora of physiological processes such as neurotransmission, excitation of skeletal, cardiac, and smooth muscle, salt transport, cell volume regulation, and acid production in internal and external compartments. Families of these channels include the voltage-gated CLC family, calcium-activated CaCC family, GABAA receptors, glycine receptors, and the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is an ATP-binding cassette (ABC) transporter that is responsible for proper fluid transport across the epithelial membrane of various cells

These are ion channels found in the membrane that can open in response to the binding of a ligand. This type of receptor has a hydrophilic channel through the middle of it, which allows ions to cross the membrane through the phospholipid bilayer (without this, it wouldn’t be able to because the bilayer is hydrophobic).

The normal cell signaling pathway of a healthy kidney includes the three Ca2+ entry pathways, the PC1/PC2, L-type/T-type, and others. PC 1 and 2 are encoding polycystins, L-type and T-type are calcium channels, and the others are also calcium channels as well. As the Ca2+ enters, it goes through P13K, which is an enzyme that is involved in cellular functions. Next, it moves on to Akt, which is a

Figure 4. Guanylate cyclase and causes ion secretion as well, but it targets guanylate cyclase

A sodium channel consists of four homologous domains with each domain containing six alpha helix transmembrane segments. The two beta segments can be used for stability, selectivity or other processes dependent on the type of channel. Each segment is labeled s1-s6 with s4 as the voltage sensor composed of positively charged amino acids which moves upwards out of the cell during cell depolarization. The s5-s6 segments line the outer pore, which is the site of ion flux. There are many isoforms of sodium channels coding in different regions of the genome and these sodium channel types also mediate specific functions in certain regions of the body. For reference, mammals contain sodium channels 1.1-1.9 (Nav1.1-Nav1.9) with known functions for

Classical Calpains, especially those found in humans, are ubiquioltly expressed and are controlled through the inhibitor of Calpastain (Trinchese et al., 2008). Although the role of calcium inducing change to enable Calpastatin to bind to Calpain is unknown, it is seen that Calpain 2 is bounded by inhibitory domains of Calpastatin which are inhibiting Calpain from both sides of the active site cleft. From this it was assumed that Calpastatin not only recognizes that there are multiple lower affinity sites but, that they are only present in the calcium-bound form of the enzyme which results in the interaction between Calpain and Calpastatin to be tight, specific and calcium dependent (Hanna, Campbell, & Davies, 2008).

Of the ten isoforms of AC that mammalian cells possess, nine of those isoforms are integral membrane proteins (mACs) and one of them is soluble or exists in the cytoplasm (sACs). The mAC isoforms are involved in the signaling pathway involving cAMP activating various target proteins in response to an extracellular stimuli, however the sAC isoform is hypothesized to be involved with a signaling pathway involved with intracellular stimuli. Cloning of the sAC revealed that it is biochemically distinct from the other isoforms and it is the more “ancient” isoform, as it closely resembles ACs found in cyanobacteria which first evolved over 3 billion years ago. The sAC is also regulated much differently than the mACs; while the nine other

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.