Biomaterial Database

Chromaffin cell action potentials and their possible role in adrenaline secretion from rat adrenal medulla. 1980

Y Kidokoro, and A K Ritchie

1. The role of action potentials in adrenaline secretion was investigated in the rat adrenal medulla. The effects of various treatments on adrenaline secretion from the perfused adrenal medulla were compared with the effects of similar treatments on spike frequency in dissociated adrenal chromaffin cells. 2. KCl concentrations between 10 and 20 mM increased the extracellularly recorded spike frequency of dissociated adrenal chromaffin cells. Upon perfusion by a KCl concentration of 30 mM there was an initial brief burst of spikes followed by a period of inactivity in the continued presence of 30 mM-Kcl. Tetrodotoxin (TTX, 6 microM) decreased the amplitude and frequency of the KCl evoked spikes. 3. The rate of adrenaline secretion from the isolated perfused rat adrenal gland increased as the KCl concentration was raised to 10 and up to 120 mM. Secretion which was evoked by KCl concentrations between 10 and 20 mM was partially inhibited by TTX. At KCl concentrations of 30 mM or greater evoked secretion was no longer affected by TTX. 4. CoCl2 (5 mM) blocked KCl increase of spike frequency and also blocked stimulation of adrenaline secretion by all concentrations of KCl tested. 5. Tetraethylammonium chloride (10 mM), which decreased spike frequency but greatly prolonged the spike duration, enhanced secretion induced by 15 mM-Kcl. 6. The results are consistent with the following interpretation. The TTX insensitive portion of the KCl stimulated adrenaline secretion is due to Ca influx through voltage dependent Ca channels which are open as a consequence of the steady-state level of KCl depolarization. The TTX sensitive portion of secretion is indicative of an extra increment of Ca influx during spike activity enhanced by KCl. This increment of Ca influx may occur through voltage dependent Ca channels whose activation is facilitated by the voltage changes caused during the TTX sensitive Na component of the spike and possibly through the Na channel itself. 7. Stimulation of secretion by acetylcholine (ACh) in the perfused adrenal medulla was half maximal at 15 microM and began to saturate around 50 microM. Release was partially inhibited by TTX only when the concentration of ACh was 10 microM or less. The possible role of action potentials in ACh stimulated adrenaline release is discussed.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011189	Potassium Chloride	A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.	Slow-K,Chloride, Potassium
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D003035	Cobalt	A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.	Cobalt-59,Cobalt 59
D004837	Epinephrine	The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.	Adrenaline,4-(1-Hydroxy-2-(methylamino)ethyl)-1,2-benzenediol,Adrenaline Acid Tartrate,Adrenaline Bitartrate,Adrenaline Hydrochloride,Epifrin,Epinephrine Acetate,Epinephrine Bitartrate,Epinephrine Hydrochloride,Epinephrine Hydrogen Tartrate,Epitrate,Lyophrin,Medihaler-Epi,Acetate, Epinephrine
D000109	Acetylcholine	A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.	2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000313	Adrenal Medulla	The inner portion of the adrenal gland. Derived from ECTODERM, adrenal medulla consists mainly of CHROMAFFIN CELLS that produces and stores a number of NEUROTRANSMITTERS, mainly adrenaline (EPINEPHRINE) and NOREPINEPHRINE. The activity of the adrenal medulla is regulated by the SYMPATHETIC NERVOUS SYSTEM.	Adrenal Medullas,Medulla, Adrenal,Medullas, Adrenal
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012636	Secretory Rate	The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa.	Rate, Secretory,Rates, Secretory,Secretory Rates