Voltage sensitive calcium channels in the presynaptic terminals of a decrementally conducting photoreceptor

Ross, William N.; Stuart, Ann E.

doi:10.1113/jphysiol.1978.sp012142

Cited by 45 publications

(51 citation statements)

References 39 publications

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“…The barnacle photoreceptor neurone does not ordinarily display a regenerative response upon depolarization. Ca action potentials, however, can be elicited from the terminal region by depolarization with light or current in the presence of TEA or 3-AP (Ross & Stuart, 1978). These compounds presumably block a K current that normally counters inward current flowing through voltage-sensitive Ca channels.…”

Section: Resultsmentioning

confidence: 99%

“…We define the 'somatic region' as the perikaryon, its dendritic processes, and the axon hillock (the first 1 mm of axon); following the D. R. EDGINGTON AND A. E. STUART convention of Ross & Stuart (1978), the final 1 mm of axon, axon branches within the commissure of the supraoesophageal ganglion, and the presynaptic terminal arborizations, are referred to as the 'terminal region'.…”

Section: Resultsmentioning

confidence: 99%

“…Voltage signals can spread the long distance to the terminals because of the high resistivity of the axonal membrane (Shaw, 1972;. Although the photoreceptor neurone does not generate propagating action potentials, its presynaptic D. R. EDGINGTON AND A. E. STUART terminal membrane contains voltage-sensitive Ca channels (Ross & Stuart, 1978); these channels presumably mediate transmitter release. It is of interest to determine whether the Ca channels are localized exclusively in the terminal membrane and excluded from the high resistivity axonal membrane, or whether they are also present in the axon.…”

Section: Introductionmentioning

confidence: 99%

“…The dissection and methods of recording from the preparation and stimulating it with light have been described elsewhere in detail ; Ross & Stuart, 1978).…”

Section: Introductionmentioning

confidence: 99%

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Calcium channels in the high resistivity axonal membrane of photoreceptors of the giant barnacle.

Edgington¹,

Stuart²

1979

The Journal of Physiology

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SUMMARY1. The distribution of calcium channels in the cell membrane of the photoreceptor neurone of the giant barnacle, Balanus nubilus, was studied by recording intracellularly in or near the soma, in the axon, and near the presynaptic terminals. The membrane properties of these different regions of the cell could be studied by separately superfusing each region with test salines or by cutting the axon between two regions.2. In the presence of tetraethylammonium (TEA) or 3-aminopyridine (3-AP), but not in their absence, Ca dependent action potentials could be evoked with depolarizing current pulses in the somatic, axonal, and terminal regions. Consequently, voltage-sensitive Ca channels and TEA-sensitive channels are present in all three regions of the cell.3. The action potentials recorded from the three regions were similar in their slow times-to-peak (30-300 msec), long durations (0-2-2 see in 100 mM-TEA), and longlasting (0-2-10 see) undershoots. The action potentials were inhibited by extracellular Co. 4. Clear differences were consistently observed between terminal action potentials and axonal or somatic action potentials in TEA. Terminal action potentials displayed a lower voltage threshold, faster rate of rise, and were less sensitive to inhibition by extracellular cobalt, suggesting that the Ca current is greater in the terminal region.5. Bathing the receptor axon in low Ca or Co solutions led to a greater attenuation of large depolarizing components of the visual signal as they spread to the presynaptic terminals.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The dissection and methods of recording from the preparation and stimulating it with light have been described elsewhere in detail ; Ross & Stuart, 1978).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calcium channels in the high resistivity axonal membrane of photoreceptors of the giant barnacle.

Edgington¹,

Stuart²

1979

The Journal of Physiology

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“…This large size enabled stable intra-cellular recordings (Gwilliam, 1963(Gwilliam, , 1965Brown, Hagiwara, Koike & Meech, 1970; , as well as intra-axonal recordings (Shaw, 1972; Ozawa, Hagiwara, Nicolaysen & Stuart, 1976;Hudspeth, Poo & Stuart, 1977; Hudspeth Ross & Stuart, 1978). These studies have revealed that illumination causes a slow, sustained depolarization but no spike 0022-3751/80/1090-0414 $07.50 © 1980 The Physiological Society H. KOIKE AND K. TSUDA potentials in the photoreceptor cell and its axon, and that this depolarizing receptor potential spreads electrotonically towards the axon terminal which is several millimetres away from the cell body (Shaw, 1972;.…”

Section: Introductionmentioning

confidence: 99%