Calcium and potassium currents of the membrane of a barnacle muscle fibre in relation to the calcium spike

Hagiwara, Susumu; Hayashi, Hideo; Takahashi, Kunitaro

doi:10.1113/jphysiol.1969.sp008955

Cited by 110 publications

(49 citation statements)

References 20 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar ionic requirements for the initiation of the action potential have been observed in crayfish muscle (Fatt and Ginsborg, 1958) and barnacle muscle (Hagiwara and Naka, 1964;Hagiwara et al, 1964). Recently Hagiwara et al (1969) have shown that, when barnacle muscle fibers are subjected to voltage-clamp conditions and perfused with internal solutions containing a calcium chelating buffer, the early increase in membrane conductance varies with the concentration of Ca ions. They also showed that the peak potential of the spike is determined not only by the early inward current but also by the late outward current which is carried by K ions.…”

Section: Discussionmentioning

confidence: 66%

The Ionic Requirements for the Initiation of Action Potentials in Insect Muscle Fibers

Washio

1972

The Journal of General Physiology

View full text Add to dashboard Cite

Electrical properties of locust leg muscle fibers were studied by means of intracellular electrodes. In most fibers, a depolarizing current pulse initiated a local response. A delayed decrease in membrane resistance appeared with more than about 10 my depolarization. In some fibers a regenerative response also was found. Membrane constants were measured, applying the short cable model. The value of the space constant X was 1.6 mm and the calculated value of Rm was about 1750 ohm cm 2 . Action potentials could be elicited when the bathing fluid contained more than 2-5 mM Ba or Sr. Similar responses were seen with 2 mM Ca in the presence of tetraethylammonium (TEA). The overshoot of these action potentials increased with increasing [Ca++] 0 , [Sr++]o, or [Ba++], the increment for a 10-fold increase being about 29 my for Ca and Sr and between 40 and 50 my for Ba. These action potentials were inhibited by Mn ions but were not affected by tetrodotoxin or procaine. In solutions containing Ba or Sr, action potentials generated were suppressed by addition of Ca. The removal of Na ions did not change the configuration of the action potential. The results suggest that an increase in permeability to Ca, Ba, or Sr ions makes a major contribution to the initiation of action potentials in this tissue.

show abstract

Section: Discussionmentioning

confidence: 66%

The Ionic Requirements for the Initiation of Action Potentials in Insect Muscle Fibers

Washio

1972

The Journal of General Physiology

View full text Add to dashboard Cite

show abstract

“…In experiments utilizing Ca-EGTA buffers in perfused cells (barnacle muscle: Hagiwara & Nakajima, 1966;Hagiwara, Hayashi & Takahashi, 1969; snail neurone: Kostyuk & Krishtal, 1977b; tunicate egg: Takahashi & Yoshii, 1978) the calcium spike or calcium current was found to be diminished significantly or eliminated when intracellular calcium was elevated. These effects also could not be accounted for by a reduced driving force on calcium.…”

Section: Discussionmentioning

confidence: 99%

Calcium‐mediated inactivation of the calcium conductance in caesium‐loaded giant neurones of Aplysia californica.

Eckert¹,

Tillotson²

1981

The Journal of Physiology

270

123

View full text Add to dashboard Cite

SUMMARY1. The intracellular potassium in giant neurones ofAplysia californica was replaced with caesium by a method utilizing the ionophore nystatin. Because caesium ions have low permeability through potassium channels, outward currents during voltageclamp depolarization were strongly curtailed after the caesium loading procedure and the subsequent wash-out of the ionophore.2. The calcium current elicited by a test voltage-clamp depolarization (pulse 2) was depressed following the entry of calcium elicited by a prior depolarization (pulse 1).3. The percentage depression of the test current was a linear function of the pulse 1 current-time integral, and thus appears to be related linearly to the amount of calcium carried into the cell during pulse 1. This linear relation was maintained when calcium entry was varied by changes in external calcium concentration, by altered pulse 1 amplitude and altered pulse 1 duration. Depression was substantially reduced by injection of EGTA, and by substitution of barium for extracellular calcium.4. The calcium current was unaffected by prior hyperpolarization ofthe membrane or by prior depolarizations to about Eca. Depression of the current was not altered by addition of extracellular 50 mm-TEA or by a strong hyperpolarization between the conditioning and test pulses. 5. The rate relaxation of the inward current during a given depolarization depended on the rate of entry and accumulation of free calcium. Relaxation under a given command potential became slower when calcium was partially replaced with magnesium so as to produce a smaller calcium current; or when accumulation of intracellular free calcium was retarded by injected EGTA or by barium substitution for extracellular calcium.6. Evidence is considered that accumulation of calcium ions at the cytoplasmic surface of the membrane leads to inactivation through an action upon the calcium conductance. Reduced driving force and intracellular surface-charge neutralization do not adequately account for the observed depression of the calcium current resulting from intracellular accumulation of calcium ions.

show abstract

“…It has been shown that procaine at a relatively low concentration in the external solution suppresses the increase in K conductance in several tissues (Shanes et al 1959;Taylor, 1959;. HAGI WARA AND Y. KIDOKORO & Nakajima, 1966;Hagiwara, Hayashi & Takahashi, 1969). The records in Fig.…”

Section: Effects Of Na Ions On the Action Potentialmentioning

confidence: 97%

Na and Ca components of action potentials in amphioxus muscle cells

Hagiwara¹,

Kidokoro²

1971

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The ionic mechanism of the action potential produced in lamella-like muscle cells of amphioxus, Branchiostoma californiense, was investigated with intracellular recording and polarization techniques.2. The resting potential and action potential overshoot in normal saline are -53 + 5 mV (S.D.) and + 29 + 10 mV (S.D.) respectively.3. The action potential is eliminated by tetrodotoxin (3 ,#M) and by replacing NaCl in the saline with Tris-chloride but maintained by replacing Na with Li.

show abstract

Calcium and potassium currents of the membrane of a barnacle muscle fibre in relation to the calcium spike

Cited by 110 publications

References 20 publications

The Ionic Requirements for the Initiation of Action Potentials in Insect Muscle Fibers

The Ionic Requirements for the Initiation of Action Potentials in Insect Muscle Fibers

Calcium‐mediated inactivation of the calcium conductance in caesium‐loaded giant neurones of Aplysia californica.

Na and Ca components of action potentials in amphioxus muscle cells

Contact Info

Product

Resources

About