The Electrogenesis of Adrenaline-Hyper-Polarization of Sympathetic Ganglion Cells in Bullfrogs

Koketsu, K.; Nakamura, Masaki

doi:10.2170/jjphysiol.26.63

Cited by 29 publications

(20 citation statements)

References 22 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The plot shows that with increasing amplitude of control ICa the current becomes more resistant to the action of baclofen. (Christ & Nishi, 1973), adrenaline-induced hyperpolarizations in bullfrog sympathetic ganglion neurones (Koketsu & Nakamura, 1976) or the acetylcholine activated M-current (Brown & Adams, 1980). In addition, a recent study on K+ channels from mammalian sarcoplasmic reticulum in planar phospholipid bilayers has revealed that Cs' is nearly as permeant as K+, although it is less conductive (Cukierman et al, 1985).…”

Section: Methodsmentioning

confidence: 99%

Inhibition of calcium currents in cultured rat dorsal root ganglion neurones by (−)‐baclofen

Dolphin

Scott

1986

British J Pharmacology

136

View full text Add to dashboard Cite

SW17 ORE1 Voltage-dependent inward calcium currents (ICa) activated in cultured rat dorsal root ganglion neurones were reversibly reduced in a dose-dependent manner by (-)-baclofen (10 LM to 100 4M).2 Baclofen (100IM) reduced the calcium-dependent slow outward potassium current (UK(Ca)). This current was abolished in calcium-free medium and by 3001M cadmium chloride. The action of baclofen on IK(Ca) was reduced when the calcium concentration in the medium was increased from 5 mM to 30 mM.3 The calcium independent fast transient voltage-dependent outward current (IK(Vt)) was also reduced by baclofen; this effect remained present when Ca2+-free medium was used to prevent contamination by IK(Ca)-4 4-Aminopyridine (500 fM) reduced IK(vt) and induced a small increase in ICa* The action of baclofen on 'Ca was partially antagonized by 4-aminopyridine. 5 GABAB receptor-mediated inhibition of 'Ca in cultured rat dorsal root ganglion neurones involves a direct mechanism rather than resulting indirectly from an increase in the residual outward potassium currents activated by depolarization. The reduction in Ik by baclofen was variable and dependent on the amplitude of control 'Ca, larger currents being more resistant to the baclofen-induced inhibition.

show abstract

Section: Methodsmentioning

confidence: 99%

Inhibition of calcium currents in cultured rat dorsal root ganglion neurones by (−)‐baclofen

Dolphin

Scott

1986

British J Pharmacology

136

View full text Add to dashboard Cite

show abstract

“…Nakamura & * Koketsu, 1972;Koketsu & Nakamura, 1976). No hyperpolarization was observed when dibutyryl cyclic AMP (1 mM) was applied to these ganglia (10 preparations); rather, the ganglia tended to depolarize (less than 1 mV) and notable depolarizations (about 2 mV) occurred when bibutyryl cyclic AMP was used in a concentration of 3 mm, which was the highest concentration used in these experiments.…”

Section: Resultsmentioning

confidence: 82%

“…The latter potential is recorded extracellularly as the P-potential and intracellularly as the slow inhibitory postsynaptic potential or slow i.p.s.p. Membrane hyperpolarizations induced by adrenaline and dopamine have been observed in mammalian (Libet & Kobayashi, 1969;Kobayashi & Libet, 1970;Libet & Tosaka, 1970;Christ & Nishi, 1971;Dun & Nishi, 1974) and amphibian (Nakamura & Koketsu, 1972;Weight, 1973;Libet & Kobayashi, 1974;Koketsu & Nakamura, 1976) sympathetic ganglia. However, the mechanisms involved in the production of the slow i.p.s.p.…”

Section: Introductionmentioning

confidence: 98%

Effects of Dibutyryl Cyclic Adenosine 3′,5′‐monophosphate and Theophylline on the Bullfrog Sympathetic Ganglion Cells

Akasu

Koketsu

1977

British J Pharmacology

View full text Add to dashboard Cite

1 Effects of dibutyryl cyclic adenosine 3′,5′‐monophosphate (dibutyryl cyclic AMP) and theophylline on bullfrog sympathetic ganglion cells were examined in order to test the hypothesis that cyclic AMP is essential for the generation of slow inhibitory postsynaptic potentials (i.p.s.ps) in these cells. 2 In the absence or presence of theophylline, dibutyryl cyclic AMP did not hyperpolarize but rather tended to depolarize ganglia that were hyperpolarized by adrenaline. 3 Theophylline augmented neither the P‐potential (slow i.p.s.p.) nor adrenaline‐induced hyperpolarization. 4 Thus, cyclic AMP does not seem to be essential for the generation of the slow i.p.s.p., at least in amphibian sympathetic ganglion cells.

show abstract

“…The hypothetical concept that neurotransmitters are able to produce the hyperpolarizations generated by an activation of the electrogenic Na+ pump has been reported in heart muscle (HAss and TRAUTWIEN, 1963), skeletal muscle (HAYS et al, 1974;CLAUSEN and FLATMAN, 1977) and bullfrog sympathetic ganglia KOKETSU, 1967,1968b;NAKAMURA and KOKETSU, 1972;WATANABE and KOKETSU, 1973;KOKETSU and NAKAMURA, 1976). Recently, this hypothesis was confirmed.…”

Section: Discussionmentioning

confidence: 91%

Electrogenesis of the slow inhibitory postsynaptic potential in bullfrog sympathetic ganglia.

Akasu

Koketsu

1983

Jpn.J.Physiol

Self Cite

View full text Add to dashboard Cite

The ionic mechanisms of the slow surface positive (P)-potential and the slow inhibitory postsynaptic potential (IPSP), an intracellularly recorded P-potential in sympathetic ganglia, were analysed by means of sucrose-gap, intracellular microelectrode techniques, and voltage clamp technique. Both the P-potential and the slow IPSP consist of two different potential components, namely the ouabain-sensitive and the ouabain-insensitive components. The ouabain-sensitive component was enhanced by a moderate conditioning hyperpolarization. This component was most reasonably explained as a potential change generated by an activation of the elctrogenic Na+ pump. The ouabaininsensitive potential component of the P-potential and the slow IPSP decreased in the amplitude and finally reversed its polarity by conditioning hyperpolarization. The reversal potential of ouabain-insensitive component of slow IPSP and slow inhibitory postsynaptic current (IPSO) was close to the Ex. The amplitude of ouabain-insensitive component of P-potential and slow IPSP was markedly decreased by an elevation of external K+ concentration. The reversal potential of ouabain-insensitive component shifted to a more positive potential level in high K+ Ringer's solution. On the other hand, it was augmented in K+-free Ringer's solution. A reduction of the membrane resistance was observed during the generation of the slow IPSP, when the membrane potential of ganglion cells was held at a membrane potential level more negative than -60 mV. The slow IPSC recorded by voltage-clamp method was associated with an increase in membrane conductance. It was concluded that the ouabain-insensitive component was generated by an activarion of K+ conductance.

show abstract

The Electrogenesis of Adrenaline-Hyper-Polarization of Sympathetic Ganglion Cells in Bullfrogs

Cited by 29 publications

References 22 publications

Inhibition of calcium currents in cultured rat dorsal root ganglion neurones by (−)‐baclofen

Inhibition of calcium currents in cultured rat dorsal root ganglion neurones by (−)‐baclofen

Effects of Dibutyryl Cyclic Adenosine 3′,5′‐monophosphate and Theophylline on the Bullfrog Sympathetic Ganglion Cells

Electrogenesis of the slow inhibitory postsynaptic potential in bullfrog sympathetic ganglia.

Contact Info

Product

Resources

About