. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GASTROPOD MODEL OF LEARNING 547 10 mV. _r - 15 mV J2 nt> -55 mV -85 mV FIGURE 39. Effects of blocking agents on voltage and voltage-clamp recordings during and after light steps (A) Voltage recordings from type B cell in ASW containing 1 mM NiCk Two microelectrodes recorded voltage simultaneously (upper two recordings). Current pulses injected through one microelectrode via a bridge circuit caused smaller voltage change during light (compared to before light) and transiently a larger voltage change after the light (com- p
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GASTROPOD MODEL OF LEARNING 547 10 mV. _r - 15 mV J2 nt> -55 mV -85 mV FIGURE 39. Effects of blocking agents on voltage and voltage-clamp recordings during and after light steps (A) Voltage recordings from type B cell in ASW containing 1 mM NiCk Two microelectrodes recorded voltage simultaneously (upper two recordings). Current pulses injected through one microelectrode via a bridge circuit caused smaller voltage change during light (compared to before light) and transiently a larger voltage change after the light (com- pared to voltage change before light) ; this indicates increased membrane resistance after light (compared to membrane resistance before light). The LLD after light persisted in NiClz when membrane resistance was not elevated. This was not so without NiCU. The LLD was reduced at more negative potentials (produced by injecting steady negative current through one micro- electrode) ; light intensity (indicated by bottom trace), X 10" erg-cm'2-sec"1 (unfiltered). (B) Voltage-clamp recordings from same cell as in (A) under same conditions at comparable holding potentials; up = inward current. Note the long-lasting inward current after light step. Voltage traces at top were recorded simultaneously with current recordings. (C) Voltage-clamp recording during and after light steps in presence of blocking agents. Voltage traces at top were recorded simultaneously with current recordings. Upper recordings in NaMree ASW, 1 mM 4-aminopyridine (4 A-P), and 1 mM NiCU were all at — 5 mV absolute holding potential. Cur- rent records at lower holding potentials were for same cell in 4-aminopyridine. Note absence of measurable early or late outward currents during and after light (intensity, X 109 erg-cm"4-sec"1, unfiltered), and presence of slowly decreasing sustained inward current (Ca2+). Dash line indi- cates steady-state current level in darkness (Alkon, 1979). T
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
