[Mast cell and blood coagulation functions during prolonged noradrenaline administration]

Area of Science:

• Pharmacology
• Histology
• Hematology

Background:

• Connective tissue mast cells play roles in various physiological processes.
• Noradrenaline is a key neurotransmitter and hormone involved in stress responses.
• Heparin is a crucial anticoagulant and biologically active substance.

Purpose of the Study:

• To investigate the effects of prolonged noradrenaline administration on mast cells in dogs.
• To analyze changes in mast cell morphology and degranulation.
• To correlate these cellular changes with alterations in the coagulation system.

Main Methods:

• Sustained intravenous infusion of noradrenaline (0.56 microgram/kg/min for 2 hours daily over six days) in canine subjects.
• Histological examination of connective tissue to quantify mast cell populations and assess morphology.
• Measurement of free heparin levels and assessment of anticoagulant activity in the hemostasis unit.

Main Results:

• A significant decrease in the total number of connective tissue mast cells was observed.
• A shift in mast cell population towards younger forms, with a reduction in mature cells.
• Evidence of marked mast cell degranulation, formation of cell clusters, and increased free heparin levels.
• Activation of the anticoagulant system, indicating a functional change in hemostasis.

Conclusions:

• Prolonged noradrenaline exposure alters mast cell populations and induces degranulation in dogs.
• The observed increase in free heparin levels suggests its release from degranulating mast cells.
• Released heparin likely contributes to the observed activation of anticoagulant hemostasis, acting as an unspecific adaptogen.