Electrically-induced catecholamine secretion by thin slices of bovine adrenal medulla

Brooks, Jack C.; Burke, David H.; Treml, Suzanne

doi:10.1016/0006-8993(80)91342-6

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Baker and Knight (1981) have shown that lactic dehydrogenase (LDH) is released from electrically permeabilized cells. We have also used release of this enzyme as a measure of the effect of electrical stimulation on the integrity of adrenal medullary tissue slices (Brooks et al, 1980). We have used LDH release from saponin-treated chromaffin cells as a measure of the ability of protein to pass through the cell membrane.…”

Section: Resultsmentioning

confidence: 99%

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Thiophosphorylation prevents catecholamine secretion by chemically skinned chromaffin cells

1984

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Section: Resultsmentioning

confidence: 99%

“…The assay was validated using purified enzyme. Lactic dehydrogenase @-Lactate: NAD+ oxidoreductase; EC 1.1.1.27) secretion was determined as described previously (Brooks et al, 1980). The enzyme was assayed on extracts of cells prepared by addition of 0.01 M potassium phosphate buffer, pH 7.5, to the cells in individual wells.…”

Section: Methodsmentioning

confidence: 99%

Thiophosphorylation prevents catecholamine secretion by chemically skinned chromaffin cells

1984

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“…Taken together, these findings suggest that electrical stimulation causes excitation of the medullary cell membrane. During the course of this study, it was reported that bovine adrenal medullary slices secreted CA on electrical stimulation (11).…”

Section: Discussionmentioning

confidence: 99%

Secretion of catecholamines from adrenal gland by a single electrical shock: electronic depolarization of medullary cell membrane.

Wakade¹,

Wakade²

1982

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

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Transmural stimulation of the isolated adrenal gland of the rat and guinea pig results in secretion of catecholamines. The secretion is due to activation of cholinergic receptors of the adrenal medulla by acetylcholine released from splanchnic nerve terminals after transmural stimulation. Our aim was to see whether the same experimental technique could be used to directly excite the adrenal medullary cell membrane by electrical stimulation and whether such stimulation would result in secretion of catecholamines. We demonstrate here that a single electrical shock to the perfused adrenal gland of the rat results in massive secretion of epinephrine and norepinephrine. The secretion is directly related to the strength and duration of the applied stimulus over a wide range. Catecholamine secretion is unaffected by tetrodotoxin or hexamethonium/atropine but is abolished by Ca2+ lack or 3 mM Mn2 . We suggest that the adrenal medullary membrane undergoes nonpropagated electrotonic depolarization on electrical stimulation and thereby voltage-dependent Ca2+ channels are opened to initiate secretion. Acetylcholine (AcCho) released from splanchnic nerves causes activation of the cholinergic receptors of the adrenal medulla followed by inward movement of Ca2", and subsequent secretion of medullary hormones. However, the precise electrophysiological changes that occur as a result of the action of AcCho on the medullary cell membrane are not completely understood. Since the early work of Cannon and Rosenblueth (1), medullary cells have been regarded as electrically insensitive. However, recent studies have shown that depolarization (2), or even action potentials (3,4), can be recorded from chromaffin cells under various conditions. Cultured adrenal chromaffin cells exhibit spontaneous action potentials and the frequency of such activity can be enhanced by AcCho (4) or excess K+ (5). Therefore, it is proposed that alteration of medullary spike activity by AcCho plays a physiological role in secretion of catecholamines (CA).Recently, it has been shown that, when the perfused adrenal gland is placed between plate electrodes and stimulated repetitively, CA are secreted (6, 7). The secretion was predominantly a result ofactivation of medullary nicotinic receptors by AcCho released from splanchnic nerves during stimulation. Thus, it was ofparticular interest to know whether medullary cell membrane could be excited by electrical stimulation and, ifelectrical stimulation did lead to a secretory response, the type of electrophysiological event that is responsible for the secretion of CA.Pharmacological analysis of our data suggests that electrical stimulation of the adrenal gland may cause nonpropagated depolarization of the medullary cells and thereby increase Ca2" influx and CA secretion. MATERIALS AND METHODSPerfusion of the left adrenal gland of the rat was carried out as described (6). Briefly, rats (250-350 g; either sex) were anesthetized with ether, and the left renal vein was cannulated after ligating other blood vess...

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Effect of various stimulus parameters on electrically-induced catecholamine secretion by thin slices of bovine adrenal medulla

Brooks

Burke

Treml

1981

J. Neural Transmission

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We examined the role of various stimulus parameters in electrically-induced catecholamine secretion by thin slices of bovine adrenal medulla. The stimulus parameters examined were voltage, duration, pulse width, and frequency for square-wave monophasic pulses. As each was examined it was held constant at a selected value for the evaluation of subsequent stimulus characteristics. For 16 mm2 tissue slices, catecholamine secretion was approximately linearly related to stimulus voltage over the range 20--80 volts, with a threshold of 20 V. Increasing the voltage beyond 80 V did not enhance secretion. Similarly, catecholamine secretion was dependent upon the frequency of stimulation. For stimuli delivered at 50 V for a 10-sec interval there was a four-fold increase in secretion over the frequency range 10--100/sec. Increasing pulse width at a constant voltage (50 V) over the range 0.4--2.0 msec resulted in a four-fold increase in catecholamine secretion. For pulses of 50 V, 50/sec and 0.8 msec pulse width, secretion was dependent upon the duration of the stimulus. Enhanced secretion was evident for times as short as 2 sec; between 5 and 15 sec of stimulation catecholamine secretion was linearly related to stimulus duration. Over the range 2--15 sec there was a five-fold enhancement of secretion. Electrically-induced catecholamine secretion by slices was markedly dependent upon stimulus parameters. In general, it was enhanced by increasing voltage, stimulus duration, pulse width and frequency. For most experiments a good choice of stimulus parameters appears to be 50 V 10 sec duration, 0.8 msec pulse width delivered at a frequency of 50/sec. Maximizing all stimulus parameters resulted in a 17-fold enhancement of secretion.

show abstract

Electrically-induced catecholamine secretion by thin slices of bovine adrenal medulla

Cited by 4 publications

References 11 publications

Thiophosphorylation prevents catecholamine secretion by chemically skinned chromaffin cells

Thiophosphorylation prevents catecholamine secretion by chemically skinned chromaffin cells

Secretion of catecholamines from adrenal gland by a single electrical shock: electronic depolarization of medullary cell membrane.

Effect of various stimulus parameters on electrically-induced catecholamine secretion by thin slices of bovine adrenal medulla

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