Mechanisms of Stimulus–Secretion Coupling in Adrenal Medulla

Rahwan, Ralf G.; Borowitz, Joseph L.

doi:10.1002/jps.2600621202

Cited by 20 publications

(3 citation statements)

References 125 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the simplicity of this premise is deceiving since recent evidence summarized in Sec. VI shows that various calcium entry blockers can inhibit norepinephrine-induced vascular smooth muscle contractions equally or more potently than potassium-induced contractions:6r88 even those contractions evoked by norepinephrine in the absence of extracellular calcium.s7 (6) Lack of effect of calcium entry blockers on calcium-induced tension development in skinned muscle fibers. This represents strong evidence for a membrane site of action of these agents, and has been demonstrated in smooths4 and cardiacs3 muscle.…”

Section: Criteria and Tests For Classifying A Drug As A Calciummentioning

confidence: 98%

“…(5) Prevention by the intracellular calcium antagonists of potassiuminduced and norepinephrine-induced vascular smooth muscle contraction, with equal potency against both stimulants. (6) Inhibition by the intracellular calcium antagonists of calciurninduced tension development in skinned cardiac or smooth muscle fibers. (7) Lack of displacement by the intracellular calcium antagonists of the positive inotropic concentration-response curves of isolated atria to excess calcium (which enters cells directly through the slow calcium channels13'), isoproterenol (which indirectly enhances calcium entry through the slow calcium ~h a n n e l s~l -~~) , or cardiac glycosides (which enhance calcium entry through membrane channels distinctly different from the slow calcium ~h a n n e l s ' l~~~-~' ).…”

Section: Criteria and Tests For Classifying A Drug As An Intracelmentioning

confidence: 99%

See 1 more Smart Citation

Mechanisms of action of membrane calcium channel blockers and intracellular calcium antagonists

Rahwan

1983

Medicinal Research Reviews

Self Cite

View full text Add to dashboard Cite

Section: Criteria and Tests For Classifying A Drug As A Calciummentioning

confidence: 98%

Section: Criteria and Tests For Classifying A Drug As An Intracelmentioning

confidence: 99%

Mechanisms of action of membrane calcium channel blockers and intracellular calcium antagonists

Rahwan

1983

Medicinal Research Reviews

Self Cite

View full text Add to dashboard Cite

“…The methylxanthine, caffeine, can stimulate a release of calcium from adrenal medullary mitochondria (Rahwan et al, 1973) and this may account for the secretion enhancing properties of this group of phosphodiesterase inhibitors. Calcium release from intramembranous or intracytoplasmic stores by cyclic AMP may occur in both presynaptic and post-synaptic neuronal elements and could account for some of the effects of extra-or intra-cellularly applied cyclic AMP and dibutyryl cyclic AMP.…”

Section: Effects Of Net + K + -A Tpase Inhibitors On the Depressionmentioning

confidence: 99%

The Role of Cyclic Nucleotides in the CNS

Phillis

1977

Can. j. neurol. sci.

111

View full text Add to dashboard Cite

SUMMARY:On the basis of the information presented in this review, it is difficult to reach any firm decision regarding the role of cyclic AMP (or cyclic GMP) in synaptic transmission in the brain. While it is clear that cyclic nucleotide levels can be altered by the exposure of neural tissues to various neurotransmitters, it would be premature to claim that these nucleotides are, or are not, essential to the transmission process in the pre- or postsynaptic components of the synapse. In future experiments with cyclic AMP it will be necessary to consider more critically whether the extracellularly applied nucleotide merely provides a source of adenosine and is thus activating an extracellularly located adenosine receptor, or whether it is actually reaching the hypothetical sites at which it might act as a second messenger. The application of cyclic AMP by intracellular injection techniques should minimize this particular problem, although possibly at the expense of new difficulties. Prior blockade of the adenosine receptor with agents such as theophylline or adenine xylofuranoside may also assist in the categorization of responses to extracellularly applied cyclic AMP as being a result either of activation of the adenosine receptor or of some other mechanism. Ultimately, the development of highly specific inhibitors for adenylate cyclase should provide a firm basis from which to draw conclusions about the role of cyclic AMP in synaptic transmission. Similar considerations apply to the actions of cyclic GMP and the role of its synthesizing enzyme, guanylale cyclase.The use of phosphodiesterase inhibitors in studies on cyclic nucleotides must also be approached with caution. The diverse actions of many of these compounds, which include calcium mobilization and block of adenosine uptake, could account for many of the results that have been reported in the literature.

show abstract

The adrenal medulla: A model for studies of hormonal and neuronal storage and release mechanisms

Helle

Serck‐Hanssen

1975

Mol Cell Biochem

View full text Add to dashboard Cite

We have observed that phospholipids and protein of the catecholamine (CA) storage granules, i.e. the chromaffin granules, interact in an in vitro system to form liposomal particles, which in many respects resemble the intact matrix of the bovine chromaffin granule. A model has been suggested which consists of an aqueous phase, containing the acidic chromogranins and intact dopamine-beta-hydroxylase (DBH) ATP and CA, embedded in a liquid crystal of the matrix phospholipids. Ca2+ may play a significant role in the sequence of functional transitions of such an organelle, not only in the accumulation of Ca2+, as during the secretory phase of the intact cell, but also as the agent inducing a separation of the outer membrane bilayer from the matrix phase to be released, as during exocytosis. Furthermore, a liposome model of the matrix may also tentatively explain the occurrence of intact matrices in the interstitium of stimulated glands. Recent evidence for the identity between chromogranin A and DBH subunits have been summarized and a possible role for the inactive subunits in the ionic binding of ATP and CA in the aqueous phase of the matrix is discussed. A role of Ca2+ and cyclic AMP in the mediation of beta-adrenergic modulation is postulated on the basis of our recent work on acetylcholine-induced release of CA from perfused and stimulated bovine adrenals. We conclude that such a beta-adrenergic modulation is secondary to that of the cholinergic response. Hence, this activation is able to enhance the output induced by mild cholinergic stimulation although insufficient to evoke a CA release by itself.

show abstract

Mechanisms of Stimulus–Secretion Coupling in Adrenal Medulla

Cited by 20 publications

References 125 publications

Mechanisms of action of membrane calcium channel blockers and intracellular calcium antagonists

Mechanisms of action of membrane calcium channel blockers and intracellular calcium antagonists

The Role of Cyclic Nucleotides in the CNS

The adrenal medulla: A model for studies of hormonal and neuronal storage and release mechanisms

Contact Info

Product

Resources

About