Adrenal chromaffin cells, catecholamine

Neurotensin-induced adrenal chromaffin cell catecholamine secretion] NEUT-R antagonist (CPA) [inhibits mast cell Histamine release]... 

Acridine orange DNA binding, 45 use in DNA intercalation, 44-58 Adrenal chromaffin cells, catecholamine detection, 75,77,78/... 

Liu PS, Kao LS, Lin MK. 1994. Organophosphates inhibit catecholamine secretion and calcium influx in bovine adrenal chromaffin cell. Toxicology 90 81-91. 

P2Y receptors that are found on endothelial cells elicit a Ca2+-dependent release of endothelium-dependent relaxing factor (EDRF) and vasodilation. A secondary activation of a Ca2+-sensitive phospholipase A2 increases the synthesis of endothelial prostacyclin, which limits the extent of intravascular platelet aggregation following vascular damage and platelet stimulation. The P2Y-mediated vasodilation opposes a vasoconstriction evoked by P2X receptors located on vascular smooth muscle cells. The latter elicit an endothelial-independent excitation (i.e. constriction). P2Y receptors are also found on adrenal chromaffin cells and platelets, where they modulate catecholamine release and aggregation respectively. 

Matsumura C, Kuwashima H, Soma S, Kimura T. 2007. Effects of genistein and herbimycin, tyrosine kinase inhibitors, on catecholamine release in bovine adrenal chromaffin cells. Auton Autacoid Pharmacol 27 181-187. 

As detailed earlier (see Section 2.2.6A.2.2), Chen et al. (2008) have recently shown with amperometry that loss of dysbindin-1 in sdy/DBA mice results in increased quantal size of vesicular epinephrine and/or norepinephrine in adrenal chromaffin cells, but that the total catecholamine amount released per stimulus is smaller due to decreased release probability. This suggests that dysbindin-1 normally facilitates adrenal epinephrine and/or norepinephrine release. 

Dar, D.E., and Zinder, O. 1998. Catecholamine secretion from bovine adrenal chromaffin cells induced by the dextrorotatory isomer of anatoxin-a. Gen Pharmacol 31, 737-740. 

Permeabilized secretory cells are widely used to study the final events during secretion by exocytosis. Convenient cellular models are bovine adrenal chromaffin cells in short term culture and the rat pheochromocytoma cell line PC 12. Both cell types take up labeled catecholamines and store them in secretory vesicles, from which they can be released upon stimulation. The released catecholamines can be detected in the supernatant. After permeabilization of the plasma membrane, release of catecholamines can be triggered by micromolar concentrations of Ca. ... 

Camphor inhibited catecholamine secretion from bovine adrenal chromaffin cells. 

Catechol-0-methyltransferase (COMT) is responsible for the second major pathway of catecholamine metabolism, catalyzing 0-methylation of dopamine to methoxytyramine, norepinephrine to normetanephrine, and epinephrine to metanephrine. COMT is not present in monoamine-producing neurons, which contain exclusively MAO, but is present along with MAO in most extraneuronal tissue. The membrane-bound isoform of COMT, which has high affinity for catecholamines, is especially abundant in adrenal chromaffin cells. As a result of the preceding and other differences in the expression of metabolizing enzymes, catecholamines produced at neuronal and adrenal medullary locations follow different neuronal and extraneuronal pathways of metabolism (Figure 29-5). 

Higuchi, H., Costa, E., Yang, W.-Y.T. (1988) Neuropeptide Y inhibits the acetylcholine-mediated release of catecholamines from bovine adrenal chromaffin cells. Pharmacol. Exp. Ther. 244, 468-474. 

Mastoparan, INLKALAALA KKILa, a 14-peptide amide found in the venom of wasps. Mastoparan degranulates mast cells and induces the release of catecholamines and serotonin from adrenal chromaffin cells or platelets. Mastoparan C, [Leu , Val ]mastoparan, and crabolin... 

Duarte CB, Rosario LM, Sena CM, Carvalho AR A toxin fraction (FTX) from the funnel-web spider poison inhibits dihydropyridine-insensitive Ca channels coupled to catecholamine release in bovine adrenal chromaffin cells. J Neurochem 1993 60(3) 908-13. 

Tong, W. and Yeung, E.S., On-column monitoring of secretion of catecholamines from single bovine adrenal chromaffin cells by capillary electrophoresis, J. Neurosci Methods, 76, 193, 1997. 

Owing to the broad spectrum of substrates for both enzymes, the sensor responds to various catecholamines, aminophenols and ferrocene derivatives. The best sensitivities were obtained for aminophenol and epinephrine where the lower limit of detection is 100 pM. The recycling sensor was used to trace the secretion of catecholamines in cultures of adrenal chromaffin cells. Furthermore both a sandwich assay for IgG and displacement of enzyme labeled cocaine have been indicated by the amplification enzyme sensor. 

Detection of catecholamines from adrenal chromaffin cells... 

Type Cl and D botulinum neurotoxins as ADP-ribosyl transferases. As shown by Knight et al. (3), type D botulinum neurotoxin was able to inhibit exocytosis in cultured chromaffin cells. Fig. 1 represents the results of our experiments showing the time course of this inhibition. When cultured bovine adrenal chromaffin cells were incubated with type D botulinum neurotoxin, inhibition of acetylcholine-evoked catecholamine release appeared. This inhibition, however, did not occur instantaneously but appeared and increased with days of incubation, suggesting involvement... 

Fig. 1. Geft) Inhibition of acetylcholine-induced catecholamine release by botulinum toxin in cultured adtenal chromaffin cells. Bovine adrenal chromaffin cells were isolated and cultured at a density of 5 x lOVml. After two days of culture, the cells were washed and suspended in a fresh medium containing 20 pg/ml of type D botulinum neurotoxin. After incubation for indicated days, the cells were washed and stimulated 500 with pM acetylcholine. Catecholamines in the media and cells were extracted separately and quantified electrochemically. Catecholamine release is expressed as % of the total amount , acetylcholine-evoked release O, basal release.

Figure 14 Experiments with a carbon fiber electrode at a single adrenal chromaffin cell exposed to 50 pM histamine for 5 s (indicated by the long bar). A 3 s exposure to a solution containing 100 nM Ca + and 50 pM epinephrine was used to postcalibrate the microsensor (shown by the short bar). In panel A, release from a single cell was evoked by histamine exposure and resulted in the amperometric spikes due to catecholamine oxidation (lower panel). At the same time, Ca release was detected. In panel B, neither catecholamine nor Ca - release was detected from a single cell after histamine exposure. I is the fluorescence intensity. Data were obtained using a 5pm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from Anal. Client, with permission [45].)...

Mojet MH, Mills E, Duchen MR. Hypoxia-induced catecholamine secretion in isolated newhom rat adrenal chromaffin cells is mimicked hy inhihition of mitochondrial respiration. J Physiol (Lond) 1997 504 175-189. 

As for the catalytic activity of TH for substrates other than tyrosine, the catalytic hydroxylation of phenylalanine by TH was reported as early as the 1960s with partially purified enzyme [146-150]. Later it was found that the hydroxylation of phenylalanine is not catalyzed by highly purified TH [143]. However, it was revealed that phenylalanine is almost as good a substrate for highly purified TH as tyrosine itself under certain experimental conditions in vitro [151] and can also be utilized for the biosynthesis of catecholamines in isolated bovine adrenal chromaffin cells [152]. The hydroxylation of L-phenylalanine gives first L-p-tyrosine as the initial product and then DOPA [152]. 

Adrenaline (epinephrine) is a catecholamine, which is released as a neurotransmitter from neurons in the central nervous system and as a hormone from chromaffin cells of the adrenal gland. Adrenaline is required for increased metabolic and cardiovascular demand during stress. Its cellular actions are mediated via plasma membrane bound G-protein-coupled receptors. 

Together with dopamine, adrenaline and noradrenaline belong to the endogenous catecholamines that are synthesized from the precursor amino acid tyrosine (Fig. 1). In the first biosynthetic step, tyrosine hydroxylase generates l-DOPA which is further converted to dopamine by the aromatic L-amino acid decarboxylase ( Dopa decarboxylase). Dopamine is transported from the cytosol into synaptic vesicles by a vesicular monoamine transporter. In sympathetic nerves, vesicular dopamine (3-hydroxylase generates the neurotransmitter noradrenaline. In chromaffin cells of the adrenal medulla, approximately 80% of the noradrenaline is further converted into adrenaline by the enzyme phenylethanolamine-A-methyltransferase. 

Three amines—dopamine, norepinephrine, and epinephrine—are synthesized from tyrosine in the chromaffin cells of the adrenal medulla. The major product of the adrenal medulla is epinephrine. This compound constimtes about 80% of the catecholamines in the medulla, and it is not made in extramedullary tissue. In contrast, most of the norepinephrine present in organs innervated by sympathetic nerves is made in situ (about 80% of the total), and most of the rest is made in other nerve endings and reaches the target sites via the circu-... 

Catecholamines, such as epinephrine secreted by the chromaffin cells of the adrenal medulla or norepinephrine produced by the pancreas, have similar actions on metabolism to those of glucagon. 

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