Premium
The spleen mediates beneficial effects of 5HT‐1A receptor agonists in hypovolemic shock
Author(s) -
Tiniakov Ruslan L,
Scrogin Karie E
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.738.14
Subject(s) - mean circulatory filling pressure , shock (circulatory) , anesthesia , medicine , blood pressure , central venous pressure , mean arterial pressure , endocrinology , heart rate
We showed that the 5HT‐1A agonist, 8‐OH‐DPAT, increases cardiac output during hypovolemic shock by a sympathetic‐dependent increase in mean circulatory filling pressure (MCFP), an index of venous tone. To determine if increased MCFP was partially due to splenic constriction and mobilization of stored blood, we examined effects of splenectomy on 8‐OH‐DPAT‐induced changes in MAP, central venous pressure (CVP), MCFP and blood gases in rats during unresuscitated hemorrhagic shock. Splenectomized and intact rats were hemorrhaged to 50 mmHg and maintained there for 25 min, then treated with either 30 nmol/kg of 8‐OH‐DPAT or 200 uL of saline, iv, and monitored for additional 35 min. 8‐OH‐DPAT rapidly increased MAP in both intact and splenectomized rats (+32 ± 5 and +24 ± 4 mmHg; P <0.01). In intact animals, this effect coincided with persistent increases in MCFP (+1.86 ± 0.33 mmHg; P <0.01) and CVP (+0.75 ± 0.4 mmHg; P <0.01) up to 35 min post treatment. In splenectomized rats, the pressor effect of 8‐OH‐DPAT was transient (~20 min) and was not accompanied by increased MCFP. By 35 min after injection, intact 8‐OH‐DPAT‐treated rats had higher venous blood oxygen saturation (33 ± 2 vs. 23 ± 3, 22 ± 3, 24 ± 2 mmHg; P <0.01), as well as higher total bicarbonates (26 ± 1 vs. 17 ± 3, 16 ± 3, 15 ± 3 mmol/L; P <0.01) and lower lactate (4.5 ± 0.4 vs. 12 ± 1.9, 13.1 ± 2.1, 13.3 ± 2.3; P <0.01), compared to all other groups. Intact 8‐OH‐DPAT‐treated rats had a lower spleen‐to‐body weight ratio than intact animals treated with saline (0.20 ± 0.01 vs. 0.25 ± 0.01; P <0.05). Our data indicate that splenic contraction is involved in the beneficial hemodynamic effect of 8‐OH‐DPAT in hypovolemic shock. Supported by HL 076162 and 072354.