Effects of adrenergic stimulants on the splenic diameter, haemoglobin content and haematocrit in anaesthetized dogs: determination of the adrenoceptor subtype responsible for changes in the splenic diameter

Ojiri, Yoshihiko; Noguchi, Katsuhiko; Chibana, Takao; Sakanashi, Mayuko

doi:10.1111/j.1748-1716.1993.tb09589.x

Cited by 25 publications

(28 citation statements)

References 26 publications

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“…Splenic contraction induced by sympathomimetic amines, such as adrenaline, causes mobilization of red blood cells (RBC) from the spleen to splenic venous blood and then a rise in arterial haematocrit 3–5 . We have also shown previously that splenic α 1 ‐adrenoceptor stimulation produces splenic contraction and thereby elicits significant increases in systemic arterial haemoglobin content and haematocrit 6 . However, whether contraction of the spleen in response to catecholamines can affect circulating blood concentrations of leucocytes and platelets remains obscure.…”

Section: Introductionmentioning

confidence: 99%

Uneven Changes In Circulating Blood Cell Counts With Adrenergic Stimulation To The Canine Spleen

Ojiri¹,

Noguchi²,

Shiroma³

et al. 2002

Clin Exp Pharmacol Physiol

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1. Responses of splenic diameter measured by sonomicrometry to alpha- and beta-adrenoceptor stimulants were estimated together with simultaneously measured systemic arterial and splenic venous concentrations of red blood cells (RBC), white blood cells (WBC) and platelets (PLT) in anaesthetized dogs. 2. Intravenous and intrasplenic arterial injections of adrenaline, noradrenaline and phenylephrine all produced profound decreases in splenic diameter. Increases in systemic arterial concentrations of RBC produced by these stimulants were observed immediately following the splenic contraction and marked increases in splenic venous concentration of RBC. 3. Adrenaline and noradrenaline both caused rapid and transient decreases in WBC release from the spleen and these agonists then, in addition to phenylephrine, caused gradual and small increases in systemic arterial WBC concentrations. The increases in arterial RBC and WBC concentrations were abolished by transient isolation of the spleen from the systemic circulation. These three agents did not significantly modify differences between splenic venous and systemic arterial concentrations of PLT. 4. Intra-arterial injections of isoprenaline caused an increase in splenic diameter and a significant decrease in the splenic venous concentration of WBC, but barely influenced the veno-arterial differences in RBC and PLT concentrations across the spleen. 5. The present results indicate that contraction of the spleen through stimulation of splenic alpha1-adrenoceptors contributes to supplying RBC but not PLT into the systemic circulation, whereas splenic beta-adrenoceptor activation leads to splenic dilatation with increased sequestration of WBC to the spleen despite no changes in the release of RBC and PLT from the spleen.

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Section: Introductionmentioning

confidence: 99%

Uneven Changes In Circulating Blood Cell Counts With Adrenergic Stimulation To The Canine Spleen

Ojiri¹,

Noguchi²,

Shiroma³

et al. 2002

Clin Exp Pharmacol Physiol

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“…The lower dose of 3 µg/kg has been shown to increase haematocrit by 1 per cent, which was not statistically significant 35. These studies were performed in healthy animals with a normal baseline PCV.…”

Section: Discussionmentioning

confidence: 88%

Phenylephrine use for blood sparing during splenectomy in a dog

Hughes¹,

Raszplewicz²

2018

Vet Rec Case Rep

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A dog with immune-mediated haemolytic anaemia was presented for splenectomy. Phenylephrine administration immediately before the removal of the spleen induced splenic contraction and significantly elevated packed cell volume. This technique conserved red blood cells and may be beneficial in euvolaemic animals to reduce the likelihood of a transfusion being required in the event of surgical haemorrhage.

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“…Stimulation of postsynaptic α 2 -adrenoceptors increased systemic vascular resistance in both arteries and veins (Cullen, 1996). A redistribution of blood may occur, but a shift to the spleen may not take place since clonidine, a classical α 2 -agonist did not change spleen diameter when injected into the intrasplenic artery (Ojiri et al, 1993). Decreased packed cell volume and total solids may be due to haemodilution.…”

Section: Discussionmentioning

confidence: 98%

Effects of Brimonidine Ingestion on Cardiovascular Responses and Renal Function in Conscious Dogs

2006

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The effects of brimonidine, an alpha(2)-adrenoceptor agonist, on blood pressure, heart rate, respiratory rate, renal function and some blood parameters were investigated in 10 dogs. Dogs were divided into two groups, low dose (LD; 0.2 mg/kg) and high dose (HD; 0.5 mg/kg) of brimonidine given orally. The alpha(2)-adrenergic antagonist yohimbine hydrochloride was injected to dogs at a dose of 0.1 mg/kg in both groups at the fifth hour after brimonidine administration. The results demonstrated that after administration of brimonidine, mean arterial blood pressure decreased dramatically at 2 h by 23% and 20% in LD and HD groups, respectively. Heart rate was decreased in a similar manner and both remained low at 5 h after brimonidine administration. Respiratory rate was decreased by 50%, while the electrocardiogram showed prolongation of the PR interval. Glomerular filtration rate (GFR) and effective renal blood flow were reduced when measured at 4 h after brimonidine ingestion in both groups, but the effect was more pronounced in the LD group. Brimonidine caused natriuresis and kaliuresis in both LD and HD groups. The packed cell volume was decreased and hyperglycaemia was detected. Most of the effects can be reversed completely after administration of yohimbine. However, yohimbine can restore GFR only partially. These data suggest that brimonidine caused cardiovascular and respiratory depression. The adverse effects of this drug can be antagonized by yohimbine, suggesting that these effects were mediated via the alpha(2)-adrenoceptor.

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Effects of adrenergic stimulants on the splenic diameter, haemoglobin content and haematocrit in anaesthetized dogs: determination of the adrenoceptor subtype responsible for changes in the splenic diameter

Cited by 25 publications

References 26 publications

Uneven Changes In Circulating Blood Cell Counts With Adrenergic Stimulation To The Canine Spleen

Uneven Changes In Circulating Blood Cell Counts With Adrenergic Stimulation To The Canine Spleen

Phenylephrine use for blood sparing during splenectomy in a dog

Effects of Brimonidine Ingestion on Cardiovascular Responses and Renal Function in Conscious Dogs

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