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Effect of dopamine and apomorphine on bone circulation
Journal De Pharmacologie
|November 1, 1981
Summary
Dopamine caused vasoconstriction in the dog tibia nutrient artery, while apomorphine had minimal effects. This study found no evidence of dopaminergic receptors in the intraosseous vascular bed, impacting our understanding of bone blood flow regulation.
Area of Science:
- Vascular Pharmacology
- Bone Physiology
- Neuropharmacology
Background:
- The intraosseous vascular bed's response to vasoactive agents is not fully understood.
- Dopamine and apomorphine are known to affect vascular tone through various mechanisms.
Purpose of the Study:
- To investigate the effects of dopamine and apomorphine on canine tibial nutrient artery perfusion pressure.
- To determine the presence and role of dopaminergic receptors in the intraosseous vasculature.
Main Methods:
- Constant-flow autoperfusion of the canine tibial nutrient artery.
- Measurement of nutrient artery perfusion pressure and carotid arterial pressure.
- Administration of dopamine and apomorphine, with subsequent blockade using various pharmacological agents and denervation.
Main Results:
- Dopamine consistently increased nutrient artery perfusion pressure, indicating a vasoconstrictor effect.
- Alpha-blocking drugs reduced but did not reverse the dopamine-induced increase in perfusion pressure.
- Apomorphine induced only a weak, inconsistent decrease in perfusion pressure, suggesting non-specific relaxation without dopaminergic receptor involvement.
Conclusions:
- Dopamine exhibits a vasoconstrictor effect on the intraosseous vasculature.
- The study found no evidence for dopaminergic receptors in the canine tibial intraosseous vascular bed.
- Apomorphine's effects appear non-specific and not mediated by dopaminergic, adrenergic, or other tested receptor systems.