Functional characterization of α1-adrenoceptor subtypes in the rabbit spleen

Oriowo, Mabayoje A.

doi:10.1007/pl00005257

Cited by 5 publications

(2 citation statements)

References 21 publications

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“…In laboratory rodents, however, extremely few smooth muscle cells are found in the capsule (Tischendorf, 1968;Kai, Nishizono and Kimura, 2000) and elastic fibers are more highly developed than the musculature (Gross, 1951;Tischendorf, 1968). A strong contraction of the spleen in rodents has also been reported in pharmacological experiments in the rat (Aboud, Schhaffi and Docherty, 1993; Burt et a!., 1995; Stam, V. Graaf and Saxena, 1998), mouse (Eltze, 1996), and rabbit (Oriowo, 1998) which is considered to be due to a large amount of smooth muscle cells.…”

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confidence: 65%

A Scanning and Transmission Electron Microscopic Study of Contractile Trabecules in the Rat Spleen

Kimura

Fusano

Tanaka

2001

Okajimas Folia Anatomica Japonica

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The fine structures of contractile trabecules in the splenic red pulp of the rat were examined by electron microscopy to elucidate their participation in the active contraction of the spleen. Numerous fine thready trabecules were developed in the red pulp. They were enveloped with a cytoplasmic layer of reticular cells and consisted of elongated smooth muscle cells, fascicles of collagenous fibrils and elastic fibers. Their fibrous components in the capsular ends extended in a triangular form of fanribs into the fibrous tunica of the capsule. Smooth muscle cell-like interstitial cells (SIC) were situated in the interfibrous spaces. Flattened SICs were affixed with cytoplasmic processes to the elastic lamina. The trabeculocapsular junctions were represented on the elastic lamina by grouped or isolated circular patches with concentrically arranged triangular processes and were also observed on the capsular serosa by plaques with scarce microvilli of serosal cells. Smooth muscle cells of the fine trabecules were equipped on the cell surface with anchoring structures to extracellular fibrous elements as previously described by Gabella (1981). Close associations were also seen between the smooth muscle cells and elastic fibers which were terminated to the fascicles of collagenous fibers. Cell-to-cell connections were expressed by fibrous connections between spiny processes and a small number of puntate intermediate junctions and nexuses. Unmyelinated nerve fibers with adrenergic terminals were seen in the intercellular spaces. We propose that for the rat spleen, the fine trabecules in the red pulp are muscular contractiles which are responsible for the active contraction due to sympathetic stimuli and the administration of alpha 1-adrenoceptor agonists, while the elastic lamina in the capsule plays a role in the comprehensive contraction of the subcapsular vascular bed.

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confidence: 65%

A Scanning and Transmission Electron Microscopic Study of Contractile Trabecules in the Rat Spleen

Kimura

Fusano

Tanaka

2001

Okajimas Folia Anatomica Japonica

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“…The contractility of the spleen has been used as a model to identify α1 receptor subtypes and to test the efficacy of α1 receptor antagonists, such as prazosin (Aboud et al, 1993, Oriowo, 1998, Bolognesi et al, 2001). Other groups have suggested that the decrease in spleen size following experimental stroke is due to profound apoptosis of the lymphocyte population in the spleen (Offner et al, 2006b).…”

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confidence: 99%

Blockade of adrenoreceptors inhibits the splenic response to stroke

Ajmo

Collier

Leonardo

et al. 2009

Experimental Neurology

132

122

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Recent studies have highlighted the involvement of the peripheral immune system in delayed cellular degeneration after stroke. In the permanent middle cerebral artery occlusion (MCAO) model of stroke, the spleen decreases in size. This reduction occurs through the release of splenic immune cells. Systemic treatment with human umbilical cord blood cells (HUCBC) 24 hours post-stroke blocks the reduction in spleen size while significantly reducing infarct volume. Splenectomy two weeks prior to MCAO also reduces infarct volume, further demonstrating the detrimental role of this organ in stroke-induced neurodegeneration. Activation of the sympathetic nervous system after MCAO results in elevated catecholamine levels both at the level of the spleen, through direct splenic innervation, and throughout the systemic circulation upon release from the adrenal medulla. These catecholamines bind to splenic α and β adrenoreceptors. This study examines whether catecholamines regulate the splenic response to stroke. Male Sprague-Dawley rats either underwent splenic denervation two weeks prior to MCAO or received injections of carvedilol, a pan adrenergic receptor blocker, prazosin, an α1 receptor blocker, or propranolol, a β receptor blocker. Denervation was confirmed by reduced splenic expression of tyrosine hydroxylase. Denervation prior to MCAO did not alter infarct volume or spleen size. Propranolol treatment also had no effects on these outcomes. Treatment with either prazosin or carvedilol prevented the reduction in spleen size, yet only carvedilol significantly reduced infarct volume (p<0.05). These results demonstrate that circulating blood borne catecholamines regulate the splenic response to stroke through the activation of both α and β adrenergic receptors.

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Pharmacokinetics and pharmacodynamic effects of tolazoline following intravenous administration to horses

Casbeer

Knych

2013

The Veterinary Journal

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Functional characterization of α1-adrenoceptor subtypes in the rabbit spleen

Cited by 5 publications

References 21 publications

A Scanning and Transmission Electron Microscopic Study of Contractile Trabecules in the Rat Spleen

A Scanning and Transmission Electron Microscopic Study of Contractile Trabecules in the Rat Spleen

Blockade of adrenoreceptors inhibits the splenic response to stroke

Pharmacokinetics and pharmacodynamic effects of tolazoline following intravenous administration to horses

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