5-Hydroxytryptamine-induced microvascular pressure transients in lungs of anaesthetized rabbits

N. Sen, M. R. Glucksberg, S. Bhattacharya*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We determined lung microvascular pressure transients induced by 5-hydroxytryptamine (5HT), by the micropuncture technique. We mechanically ventilated anaesthetized (halothane 0.8%), open-chested rabbits, in which we recorded pulmonary artery (PA), left atrial (LA) and carotid artery pressures and cardiac output. For 4-min periods of stopped ventilation, we constantly inflated the lung with airway pressure of 7 cmH2O, then micropunctured the lung to determine pressures in arterioles and venules of 20-25 μm diameter. An intravenous bolus infusion of 5HT (100 μg), increased total pulmonary vascular resistance by 59%. Prior to 5HT infusion, the arterial, microvascular and venous segments comprised 30, 50 and 19% of the total pulmonary vascular pressure drop, respectively. However 14 s after 5HT infusion, the PA-arteriole pressure difference (arterial pressure drop) increased 46%, while the venule-LA pressure difference (venous pressure drop) increased > 100%. The arteriole-venule pressure difference (microvascular pressure drop) was abolished. The increase in the arterial pressure drop was maintained for 4.8 min, whereas the increased venous pressure drop reverted to baseline in < 1 min. We conclude that in the rabbit lung in situ, a 5HT bolus causes sustained arterial constriction and a strong but transient venous constriction.

Original languageEnglish (US)
Pages (from-to)81-87
Number of pages7
JournalActa Physiologica Scandinavica
Volume172
Issue number2
DOIs
StatePublished - 2001

Keywords

  • Compensatory vasodilatation
  • Lung micropuncture
  • Pulmonary circulation
  • Segmental pressures
  • Servonull method

ASJC Scopus subject areas

  • Physiology

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