Two Calcium Currents in Normal Rat Anterior Pituitary Cells Identified by a Plaque Assay

DeRiemer, Susan A.; Sakmann, Bert

doi:10.1007/978-3-642-70744-5_13

Cited by 34 publications

(37 citation statements)

References 31 publications

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“…The rapid inactivation is therefore attributable to a voltage-dependent "gate." Hence, the slowly deactivating Ca channels in adrenal glomerulosa cells are similar to the T-type Ca channels found in some types of excitable cells (16,(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35).…”

Section: Resultssupporting

confidence: 56%

Ca channels in adrenal glomerulosa cells: K+ and angiotensin II increase T-type Ca channel current.

Cohen

McCarthy

Barrett

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

181

101

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Ca channel currents were studied in freshly dispersed bovine adrenal glomerulosa cells to better understand the control of aldosterone secretion by extracellular K concentration (K.) and angiotensin II (All). The whole-cell variation of the patch voltage clamp technique was used. Two types of Ca channels were found. One type is similar to the "T-type" Ca channels found in many excitable cells. These channels deactivate slowly (x 7 ms at -75 mV) and inactivate rapidly during strong depolarizations. The second channel type activates and inactivates at more positive potentials than the T-type Ca channels and deactivates rapidly.

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Section: Resultssupporting

confidence: 56%

Ca channels in adrenal glomerulosa cells: K+ and angiotensin II increase T-type Ca channel current.

Cohen

McCarthy

Barrett

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

181

101

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“…In eggs (Hagiwara et al 1975;Fox & Krasne, 1984), rat d.r.g. cells (Carbone & Lux, 1986b) and rat pituitary cells (DeRiemer & Sakmann, 1986), the current carried by these channels is comparable to or is even larger than that through the high-threshold channels. Thus, besides generating and pace-making spikes, the l.v.a.…”

Section: Separation Of Lva Currentsmentioning

confidence: 82%

“…type was first postulated by Llinas & Yarom (1981) to control the firing behaviour of neurones in in vitro preparations of the inferior olive, the thalamus (Linas & Jahnsen, 1982) and the dorsal horn (Murase & Randic, 1983). Clonal lines and primary cultures of rat pituitary cells (Armstrong & Matteson, 1985;DeRiemer & Sakmann, 1986), hypothalamic neurones (Carbone & Lux, 1986b), retinal ganglion cells (Grantyn, Johnson & Lux, 1986), hippocampal neurones (Yaari, Hamon & Lux, 1986) and mouse neuroblastoma hybrid cells (Bodewei, Hering, Schubert & Wollenberger, 1985) have been shown to possess Ca2+ currents with kinetic and selectivity properties similar to those described here. Recently, an l.v.a.…”

Section: Separation Of Lva Currentsmentioning

confidence: 99%

“…In vertebrate dorsal root ganglion neurones (Carbone & Lux, 1984a;Bossu, Feltz & Thomann, 1985;Fedulova, Kostyuk & Veselovsky, 1985;Nowycky, Fox & Tsien, 1985) and rat pituitary cells (Matteson & Armstrong, 1986;DeRiemer & Sakmann, 1986) the two types of Ca2+ channels show different ranges of voltage activation and different inactivation time courses. The low-voltage-activated (l.v.a.)…”

Section: Introductionmentioning

confidence: 99%

“…Ca2+ channel. This is needed since this channel has been implicated in the control of various cellular functions, such as: (1) modulation of the cyclical firing patterns of central mammalian neurones (Llinas & Yarom, 1981); (2) regulation of hormone secretion in endocrine cells (DeRiemer & Sakmann, 1986); (3) contraction of slow muscles in molluscs (Mackie & Meech, 1985); and (4) beating of the ciliary system in protozoa (Deitmer, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Kinetics and selectivity of a low‐voltage‐activated calcium current in chick and rat sensory neurones.

Carbone

Lux

1987

The Journal of Physiology

405

221

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SUMMARY1. Using the whole-cell recording mode of the patch-clamp technique, we have investigated kinetic and selectivity properties of a low-voltage-activated (l.v.a.) Ca2+ current in chick and rat dorsal root ganglion (d.r.g.) neurones.2. L.v.a currents were activated at about -50 mV and reached maximum amplitudes between -30 and -20 mV with averages of -0-16 nA in chick and -03 nA in rat d.r.g. cells with 5 mM-extracellular Ca2+. Between -60 and -20 mV, the time to peak, tp, of this current decreased with increasing membrane depolarizations. An e-fold change of tp required a 14 mV potential change in chick and a 17 mV change in rat d.r.g. cells at 22 'C.3. Between -50 and + 20 mV inactivation of this current was fast, single exponential and voltage dependent. In rat, the time constant of inactivation, Th, was smaller and less voltage dependent than in chick.4. The amplitude of these currents increased by a factor of 5-10, when the extracellular Ca2+ concentration was changed from 1 to 95 mm. Amplitudes and kinetic parameters of the currents showed typical shifts along the voltage axis. No correlation between Ca2+ current amplitudes and activation-inactivation kinetics was found, suggesting that the reaction rates which control these processes are not dependent on Ca2+ entry. Recovery from inactivation was voltage dependent and developed with a timeconstant, Tr' in the order of 1 s. Tr was nearly halved by changing the potential from -80 to -120 mV.6. Tail currents associated with membrane repolarization were also voltage dependent and developed exponentially. Their time constant decreased by a factor of 3 when the potential was changed from -60 to -100 mV.7. A second and more prominent Ca2+ current was activated at potentials positive to -20 mV h.v.a.), masking the time course of l.v.a. currents. Between -20 and 0 mV, time to peak of the entire current increased by a factor of 2 but decreased again at higher membrane potentials. Inactivation also became significantly slower in this potential range.8. The contribution of the h.v.a. component to the total membrane current was

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Effects of dopamine and noradrenaline on Ca channels of cultured sensory and sympathetic neurons of chick

1986

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The effects of noradrenaline and dopamine on voltage-dependent Ca currents were investigated in cultured dorsal root and sympathetic ganglion neurons from chick embryos. At concentrations of 1 to 10 microM, bath application of the neurotransmitters caused a general depression of inward Ca currents. Above -20 mV the decrease of the current amplitude was reversible and accompanied by a 2-10-fold prolongation of the activation time course. Below -20 mV, where a low voltage-activated Ca component is turned on, the size of the currents was reduced by 40% with little effect on the time course. Despite extensive wash-out, little sign of reversibility was observed in this case. Single-channel current recording in outside-out membrane patches revealed that at low membrane potentials dopamine and noradrenaline reversibly reduced single Ca-channel activity. This finding supports the view that in sensory and sympathetic neurons, both neurotransmitters affect the membrane conductance by modulating Ca permeability and not by activating catecholamine-specific channels able to carry transient outward currents. The probability of Ca channel opening is strongly reduced by addition of 10 microM of either catecholamine to the bath. The possible involvement of a voltage-dependent block of Ca channels by the neurotransmitters is discussed.

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Two Calcium Currents in Normal Rat Anterior Pituitary Cells Identified by a Plaque Assay

Cited by 34 publications

References 31 publications

Ca channels in adrenal glomerulosa cells: K+ and angiotensin II increase T-type Ca channel current.

Ca channels in adrenal glomerulosa cells: K+ and angiotensin II increase T-type Ca channel current.

Kinetics and selectivity of a low‐voltage‐activated calcium current in chick and rat sensory neurones.

Effects of dopamine and noradrenaline on Ca channels of cultured sensory and sympathetic neurons of chick

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