{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,10]],"date-time":"2025-09-10T22:09:19Z","timestamp":1757542159150},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1980,7,1]],"date-time":"1980-07-01T00:00:00Z","timestamp":331257600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[1980,7]]},"abstract":"<jats:p>1. In Na\u2010 and Ca\u2010free external solutions, Sr or Ba (but not Mg) could act as carriers of inward current during action potentials in the neurone, R15 of the Aplysia abdominal ganglion. These action potentials exhibited a prolonged plateau phase, the duration of which was dependent on the concentration and species of divalent cation and activity of the neurone. 2. Depolarization of the soma membrane in Na\u2010free Ba solution generated a prolonged, \u2018late\u2019 inward current the amplitude of which was dependent on the external Ba concentration. The Ba current was insensitive to tetrodotoxin but could be blocked by Mn2+ and Co2+ ions. 3. The peak current\u2010voltage relation and threshold for activation of the late inward current was shifted to more negative potentials on replacement of Ca with Ba. The zero\u2010current (reversal) potentials for both Sr and Ba were more negative than for Ca, indicating that the \u2018Ca\u2019 channel is less permeable to Sr2+ or Ba2+ ions than to Ca2+ ions. 4. Inactivation of the \u2018Ca\u2019 channel is slower in Ba than in Ca solution. The time course of Ba currents during a maintained depolarization of 2 sec could be reasonably described by the expression, I'Ba(t) = I'Ba (infinity) [1\u2010exp(\u2010t\/tau M)]2exp(\u2010t\/tau H). 5. Time constants for activation (tau M) and inactivation (tau H) were voltage\u2010dependent. In the range \u201010 to +30 mV, tau M varied from 15 to 5 msec and tau H from 2.0 to 0.5 sec (12 degrees C). Steady\u2010state Ba conductance (corrected for inactivation) was voltage\u2010dependent, increasing sigmoidally with depolarization to a maximum of approximately 12 microS at potentials beyond +15 mV. 6. Steady\u2010state inactivation of Ba conductance (hBa(infinity)) varied with holding potential (VH). Conditioning holding potentials more negative than the resting potential (\u201040 to \u201050 mV) produced depression of Ba currents. Complete inactivation of Ba currents occurred at holding potentials more positive than 0 mV or with repetitive activation at frequencies greater than 1 Hz. 7. The divalent ions, Ba2+ and Sr2+, reversible depressed the total delayed K+ current at a rate dependent on the frequency of activation. Ba and Sr shifted the delayed K+ current\u2010voltage curve to more positive voltages and depressed the delayed outward current at all membrane potentials. 8. Comparison of the effect of Ba on delayed K+ currents with those obtained in the presence of Mn2+ ions indicated that Ba2+ ions depress both the voltage\u2010dependent and Ca\u2010dependent components of the delayed K+ current. However, the mechanism by which Ba acts to inhibit the two components of the delayed K+ current appears to be different.<\/jats:p>","DOI":"10.1113\/jphysiol.1980.sp013325","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T07:21:11Z","timestamp":1418973671000},"page":"297-313","source":"Crossref","is-referenced-by-count":27,"title":["Divalent ion currents and the delayed potassium conductance in an Aplysia neurone."],"prefix":"10.1113","volume":"304","author":[{"given":"D J","family":"Adams","sequence":"first","affiliation":[]},{"given":"P W","family":"Gage","sequence":"additional","affiliation":[]}],"member":"311","published-online":{"date-parts":[[1980,7]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1980.sp013325","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1980.sp013325","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,11,5]],"date-time":"2023-11-05T09:24:00Z","timestamp":1699176240000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1980.sp013325"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1980,7]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1980,7]]}},"alternative-id":["10.1113\/jphysiol.1980.sp013325"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1980.sp013325","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1980,7]]}}}