5‐Hydroxytryptamine Release from Enterochromaffin Granules in vitro

Penttilä, Antti; Saris, Nils‐Erik L.

doi:10.1111/j.1365-201x.1968.tb10936.x

Cited by 2 publications

(3 citation statements)

References 32 publications

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“…These results are in line with others (2,4), showing that both 5-HT storage granules and mitochondria are sedimented together by the same centrifugation force.…”

Section: Electron Microscopy Of Fraction Epsupporting

confidence: 81%

“…About 5 g of mucous membrane was homogenized in ice-cold 0.32 M sucrose with a Teflon pestle in one stroke and made up to about 50 ml. The preparation and fractionation of primary fractions were carried out as described by Penttila and Saris (4), with a slight modification. Fraction P, (debris) was separated by centrifuging the homogenate at 800 g for 10 minutes.…”

Section: Removal and Fractionation Of Mucous Membranementioning

confidence: 99%

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The Isolation of Highly 5-Hydroxytryptamine Concentrated Fraction From Rabbit Duodenal Mucous Membrane Homogenates

1971

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Large amounts of 5-hydroxytryptamine (5-HT) in the mammalian duodenum are found mainly in the enterochromaffin cells. Baker (1) was the first to demonstrate that in the enterochromaffin cells of the dog's duodenal mucosa, 5-HT was stored in large granules which were sedimented in the gravitational field used for the sedimentation of mitochondria. By further equilibrium centrifugation in a sucrose density gradient the granules were partially purified from mitochondria (2). Prusoff (3) reported that even with a two density gradient centrifugation of the mitochondrial fraction succinic dehydro genase (SDH) activity was still found in the fraction that was rich in 5-HT. Therefore, in this paper an attempt has been made to separate 5-HT storage granules from SDH. Attention has also been given to minimizing damage to the granules during separation. For this purpose urografin density gradients have been employed. MATERIALS AND METHODS Removal and fractionation of mucous membraneBoth sexes of adult rabbits, weighing about 2.0 kg, were killed by bleeding. About 50 cm of the duodenum just caudal to the pyrlous was dissected and washed thoroughly in ice-cold 0.32 M sucrose solution. All steps following removal of the duodenum were performed at 4 C. The duodenal mucous membrane was removed by scraping with a glass slide and weighed. About 5 g of mucous membrane was homogenized in ice-cold 0.32 M sucrose with a Teflon pestle in one stroke and made up to about 50 ml. The preparation and fractionation of primary fractions were carried out as described by Penttila and Saris (4), with a slight modification. Fraction P, (debris) was separated by centrifuging the homogenate at 800 g for 10 minutes. This fraction P, was washed with 0.32 M sucrose solution by suspending it in about 50 ml and recentrifuging it at 800 g for 10 minutes. The two supernatants from fraction P, were combined and centrifuged at 20,000 g for 20 min utes, providing a particulate fraction P2 and a supernatant (S2). The P2 pellet was washed gently with I ml of 0.32 M sucrose solution and recentrifuged as mentioned above. This procedure was repeated and the two superantants so obtained were combined to fraction S2. Subfractionation of fraction P2The three tubes of the HITACHI swing rotor RPS 25 were prepared by layering each 5 ml of urografin solution (5) diluted with distilled water in the following steps; 25 %, 30 %, 35 % and 40 % with 40 % solution at the bottom of the tube. The Pi pellet was sus pended in 30 ml of 0.32 M sucrose solution, each 10 ml of which was layered carefully on top of the discontinuous density gradient and then centrifuged at 60,000 g for 30 minutes. This procedure yielded A, B, C, D and E fractions (Fig. 1) which were separated serially from the top by careful aspiration. 5-HT determination5-HT amount in each fraction was determined fluorimetrically by a modification of the method of Snyder, Axelrod and Zweig (6). The pellet fractions were homogenized in 0.4 N HCIO4 at 4°C and were centrifuged at 11,500 g for 20 minutes and 3 ml of the...

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“…These results are in line with others (2,4), showing that both 5-HT storage granules and mitochondria are sedimented together by the same centrifugation force.…”

Section: Electron Microscopy Of Fraction Epsupporting

confidence: 81%

Section: Removal and Fractionation Of Mucous Membranementioning

confidence: 99%

The Isolation of Highly 5-Hydroxytryptamine Concentrated Fraction From Rabbit Duodenal Mucous Membrane Homogenates

1971

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“…It has been shown that 5-HT can be released in riitro from the granules of EC by various means. Thus, detergents, elevation of temperature, freezing, increase of the pH and decrease in the molarity of the incubation medium induce a marked decrease of 5-HT in EC granules (Penttila and Saris 1968). This release in vitro of 5-HT from granules in the EC is in many ways similar to the release of noradrenaline (NA) from adrenal medullary and nerve granules (Hillarp 1958, Euler and Lishajko 1961a and b, Lembeck and Held 1966.…”

mentioning

confidence: 97%

A Possible Vagal Adrenergic Release of Serotonin from Enterochromaffin Cells in the Cat

Ahlman

Lundberg

Dahlström

et al. 1976

Acta Physiologica Scandinavica

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The intracellular concentrations of serotonin (5-HT) in enterochromaffin cells (EC) in the cat small intestine have been studied by a cytofluorimetric method before and after long-lasting efferent vagal nerve stimulation in the neck. Such stimulation induces a decrease of 5-HT in EC of the gut as observed previously. Pretreatment with atropine could not block this decrease, suggesting a noncholinergic mechanism. Pretreatment with a beta-blocking agent, propranolol, or bilateral removal of the superior cervical ganglia could, however, block this 5-HT decrease. Pretreatment with an alpha-blocking agent, phenoxybenzamine, caused an increase in the 5-HT content of EC both with and without nerve stimulation; the reason for this is obscure. The results indicate, that vagal nerve stimulation induces a neurogenic 5-HT release from EC in the gut, and that adrenergic fibres, originating in the superior cervical ganglia, mediate this release probably via a beta-receptor mechanism. Whether or not an alpha-receptor mechanism is also involved cannot be judged at present.

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5‐Hydroxytryptamine Release from Enterochromaffin Granules in vitro

Cited by 2 publications

References 32 publications

The Isolation of Highly 5-Hydroxytryptamine Concentrated Fraction From Rabbit Duodenal Mucous Membrane Homogenates

The Isolation of Highly 5-Hydroxytryptamine Concentrated Fraction From Rabbit Duodenal Mucous Membrane Homogenates

A Possible Vagal Adrenergic Release of Serotonin from Enterochromaffin Cells in the Cat

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