Detecting Action Potentials in Neuronal Populations with Calcium
... action potentials, which can produce generalized calcium accumulations throughout the cell, due to the backpropagation of the spike (24), and (iii) calcium spikes, which can produce generalized calcium influxes that are much larger than those produced by sodium spikes (26). Thus, it is possible to d ...
... action potentials, which can produce generalized calcium accumulations throughout the cell, due to the backpropagation of the spike (24), and (iii) calcium spikes, which can produce generalized calcium influxes that are much larger than those produced by sodium spikes (26). Thus, it is possible to d ...
Presentation 3
... can be expressed in terms of the (-) second derivative of potential. In this case, the equation is one-dimensional (radially symmetric). ...
... can be expressed in terms of the (-) second derivative of potential. In this case, the equation is one-dimensional (radially symmetric). ...
International Journal of Mass Spectrometry Triacetone triperoxide
... formation of [TATP + H]+ ions by reducing the collision-induced dissociation. Fig. 4 displays the mass spectra measured for air and TATP vapor at a reduced-field E/N = 50 Td optimized according to the intensity dependence of product ions on the E/N values. Operating at such a low reduced-field, the [T ...
... formation of [TATP + H]+ ions by reducing the collision-induced dissociation. Fig. 4 displays the mass spectra measured for air and TATP vapor at a reduced-field E/N = 50 Td optimized according to the intensity dependence of product ions on the E/N values. Operating at such a low reduced-field, the [T ...
Class notes - Bullis Haiku
... Suppose you want to identify WHICH ions precipitate out of solution in the first 4 groups or are left in solution (Group V). We can actually identify which ions are present based on the solubility of the complex ions. I will show you how you can identify which ions are present in the Group I precipi ...
... Suppose you want to identify WHICH ions precipitate out of solution in the first 4 groups or are left in solution (Group V). We can actually identify which ions are present based on the solubility of the complex ions. I will show you how you can identify which ions are present in the Group I precipi ...
Roles of ion channels and transporters in guard cell signal
... stomatal opening and decreased rates of water loss as compared with wild-type plants, confirming the importance of guard cell NO 3 uptake by AtNRT1.1 under these conditions [21]. 2.4. K+ channels: properties and regulation Plant K+ channels expressed at the GC PM play a major role in the K+ uptake a ...
... stomatal opening and decreased rates of water loss as compared with wild-type plants, confirming the importance of guard cell NO 3 uptake by AtNRT1.1 under these conditions [21]. 2.4. K+ channels: properties and regulation Plant K+ channels expressed at the GC PM play a major role in the K+ uptake a ...
Chapter 3 Electric Potential
... When moving from A to C, the change in potential is ∆VCA = − E0 y . On the other hand, when going from C to B, ∆VBC = 0 since the path is perpendicular to the direction of E . Thus, the same result is obtained irrespective of the path taken, consistent with the fact that E is conservative. Notice th ...
... When moving from A to C, the change in potential is ∆VCA = − E0 y . On the other hand, when going from C to B, ∆VBC = 0 since the path is perpendicular to the direction of E . Thus, the same result is obtained irrespective of the path taken, consistent with the fact that E is conservative. Notice th ...
Signal summation occurs when impulses add together to
... One neuron often has input from many presynaptic neurons, whether excitatory or inhibitory; therefore, inhibitory postsynaptic potentials (IPSPs) can cancel out EPSPs and vice versa. The net change in postsynaptic membrane voltage determines whether the postsynaptic cell has reached its threshold o ...
... One neuron often has input from many presynaptic neurons, whether excitatory or inhibitory; therefore, inhibitory postsynaptic potentials (IPSPs) can cancel out EPSPs and vice versa. The net change in postsynaptic membrane voltage determines whether the postsynaptic cell has reached its threshold o ...
MEMBRANE PROTEINS SYNTHESIZED BY
... the isolated enzyme forms stable interactions with high affinity for a limited number of sites on the cytoplasmic face of the membrane (21). Rabbit reticulocytes contain, with possibly one or two exceptions (22), the same proteins in their membranes as do rabbit erythrocytes. We recently showed that ...
... the isolated enzyme forms stable interactions with high affinity for a limited number of sites on the cytoplasmic face of the membrane (21). Rabbit reticulocytes contain, with possibly one or two exceptions (22), the same proteins in their membranes as do rabbit erythrocytes. We recently showed that ...
Dendritic Signal Integration
... about the differences between these dendritic inhibitory synapses and their counterparts on the soma and axon, an understanding of cable theory informs speculation about the possibly specialized role of dendritic inhibition. Just as EPSPs are attenuated and filtered between the dendrites and the som ...
... about the differences between these dendritic inhibitory synapses and their counterparts on the soma and axon, an understanding of cable theory informs speculation about the possibly specialized role of dendritic inhibition. Just as EPSPs are attenuated and filtered between the dendrites and the som ...
Membrane Bistability in Olfactory Bulb Mitral Cells
... Bistable mitral cells spontaneously alternated between the downstate and the upstate. The depolarizing transition from the downstate to the upstate was initially slow, with increasing slope on approach to the upstate. This transition, designated the “depolarizing ramp,” was accurately described by a ...
... Bistable mitral cells spontaneously alternated between the downstate and the upstate. The depolarizing transition from the downstate to the upstate was initially slow, with increasing slope on approach to the upstate. This transition, designated the “depolarizing ramp,” was accurately described by a ...
Early steps in cold sensing by plant cells: the role of actin
... not detectably affected after 48 h CA or during deacclimatization (Figure 1), are also not affected by BA treatment (Figure 2a). Thus the effects of BA on cas30 transcript levels do not re¯ect a general down-regulation of transcription. CA in alfalfa suspension cells involves a rapid in¯ux of Ca2+ i ...
... not detectably affected after 48 h CA or during deacclimatization (Figure 1), are also not affected by BA treatment (Figure 2a). Thus the effects of BA on cas30 transcript levels do not re¯ect a general down-regulation of transcription. CA in alfalfa suspension cells involves a rapid in¯ux of Ca2+ i ...
Nav1.5 cardiac sodium channels, regulation and clinical implications
... cytoskeleton, like the one caused by the anticarcinogenic agent taxol (TXL) reduces the expression of Nav1.5 in the sarcolemma, and reduces the INa in a process that may or may not involve the β1 subunit by producing a reduction in fast inactivation in the Nav1.5 + β1 interaction (33). Another Nav1. ...
... cytoskeleton, like the one caused by the anticarcinogenic agent taxol (TXL) reduces the expression of Nav1.5 in the sarcolemma, and reduces the INa in a process that may or may not involve the β1 subunit by producing a reduction in fast inactivation in the Nav1.5 + β1 interaction (33). Another Nav1. ...
Nav1.5 cardiac sodium channels, regulation and
... cytoskeleton, like the one caused by the anticarcinogenic agent taxol (TXL) reduces the expression of Nav1.5 in the sarcolemma, and reduces the INa in a process that may or may not involve the β1 subunit by producing a reduction in fast inactivation in the Nav1.5 + β1 interaction (33). Another Nav1. ...
... cytoskeleton, like the one caused by the anticarcinogenic agent taxol (TXL) reduces the expression of Nav1.5 in the sarcolemma, and reduces the INa in a process that may or may not involve the β1 subunit by producing a reduction in fast inactivation in the Nav1.5 + β1 interaction (33). Another Nav1. ...
Excitatory Postsynaptic Potentials Trigger a Plateau Potential in Rat
... day 14 (P14) to P20 rats. We found that activation of glutamate receptor-mediated excitatory synaptic potentials (EPSPs) evoked a plateau potential in a subpopulation of STN neurons (n ⫽ 13/22), in a voltage-dependent manner. Plateau potentials could be induced only when the cell was hyperpolarized ...
... day 14 (P14) to P20 rats. We found that activation of glutamate receptor-mediated excitatory synaptic potentials (EPSPs) evoked a plateau potential in a subpopulation of STN neurons (n ⫽ 13/22), in a voltage-dependent manner. Plateau potentials could be induced only when the cell was hyperpolarized ...
Ksp Problem Sets 1 and 2
... Since the reactant is always a solid, there is no denominator on solubility equilibrium expressions. Assume that the denominator is always “1”. There are two basic types of Ksp problems: 1. Give the solubility (also known as the concentration of a saturated solution), find the Ksp. 2. Given the Ksp, ...
... Since the reactant is always a solid, there is no denominator on solubility equilibrium expressions. Assume that the denominator is always “1”. There are two basic types of Ksp problems: 1. Give the solubility (also known as the concentration of a saturated solution), find the Ksp. 2. Given the Ksp, ...
isolation and characterization of membranes from the cells of maize
... Mg2+-ATPase at pH 6-5. The enzymic activity was investigated with endogenous sterols as well as with added /?-sitosterol. The addition of /?-sitosterol enhanced the activity by 2-4-fold in the various membrane fractions. The high recovery (135 %) could be due to dilution of an inhibitor or activatio ...
... Mg2+-ATPase at pH 6-5. The enzymic activity was investigated with endogenous sterols as well as with added /?-sitosterol. The addition of /?-sitosterol enhanced the activity by 2-4-fold in the various membrane fractions. The high recovery (135 %) could be due to dilution of an inhibitor or activatio ...
Local anaesthetics
... duration of infiltration anaesthesia may be doubled by addition of adrenaline to the solution of local anaesthetic wit exception of tissues supplied by end-arteries. peripheral nerve block anaesthesia - achieved by injection of local anaesthesia in the vicinity of peripheral nerves or nerve plexus ...
... duration of infiltration anaesthesia may be doubled by addition of adrenaline to the solution of local anaesthetic wit exception of tissues supplied by end-arteries. peripheral nerve block anaesthesia - achieved by injection of local anaesthesia in the vicinity of peripheral nerves or nerve plexus ...
OSMOSIS (A self-instructional package)
... 2. Write van't Hoff's Law (π = iRTc) and use this equation to estimate the osmotic pressure of a solution. State that van't Hoff's Law applies exactly only to very dilute solutions. 3. State that the osmotic coefficient (Φ) is used to correct for deviations of real solutions from the predictions of ...
... 2. Write van't Hoff's Law (π = iRTc) and use this equation to estimate the osmotic pressure of a solution. State that van't Hoff's Law applies exactly only to very dilute solutions. 3. State that the osmotic coefficient (Φ) is used to correct for deviations of real solutions from the predictions of ...
Membrane potential
Membrane potential (also transmembrane potential or membrane voltage) is the difference in electric potential between the interior and the exterior of a biological cell. With respect to the exterior of the cell, typical values of membrane potential range from –40 mV to –80 mV.All animal cells are surrounded by a membrane composed of a lipid bilayer with proteins embedded in it. The membrane serves as both an insulator and a diffusion barrier to the movement of ions. Ion transporter/pump proteins actively push ions across the membrane and establish concentration gradients across the membrane, and ion channels allow ions to move across the membrane down those concentration gradients. Ion pumps and ion channels are electrically equivalent to a set of batteries and resistors inserted in the membrane, and therefore create a voltage difference between the two sides of the membrane.Virtually all eukaryotic cells (including cells from animals, plants, and fungi) maintain a non-zero transmembrane potential, usually with a negative voltage in the cell interior as compared to the cell exterior ranging from –40 mV to –80 mV. The membrane potential has two basic functions. First, it allows a cell to function as a battery, providing power to operate a variety of ""molecular devices"" embedded in the membrane. Second, in electrically excitable cells such as neurons and muscle cells, it is used for transmitting signals between different parts of a cell. Signals are generated by opening or closing of ion channels at one point in the membrane, producing a local change in the membrane potential. This change in the electric field can be quickly affected by either adjacent or more distant ion channels in the membrane. Those ion channels can then open or close as a result of the potential change, reproducing the signal.In non-excitable cells, and in excitable cells in their baseline states, the membrane potential is held at a relatively stable value, called the resting potential. For neurons, typical values of the resting potential range from –70 to –80 millivolts; that is, the interior of a cell has a negative baseline voltage of a bit less than one-tenth of a volt. The opening and closing of ion channels can induce a departure from the resting potential. This is called a depolarization if the interior voltage becomes less negative (say from –70 mV to –60 mV), or a hyperpolarization if the interior voltage becomes more negative (say from –70 mV to –80 mV). In excitable cells, a sufficiently large depolarization can evoke an action potential, in which the membrane potential changes rapidly and significantly for a short time (on the order of 1 to 100 milliseconds), often reversing its polarity. Action potentials are generated by the activation of certain voltage-gated ion channels.In neurons, the factors that influence the membrane potential are diverse. They include numerous types of ion channels, some of which are chemically gated and some of which are voltage-gated. Because voltage-gated ion channels are controlled by the membrane potential, while the membrane potential itself is influenced by these same ion channels, feedback loops that allow for complex temporal dynamics arise, including oscillations and regenerative events such as action potentials.