Dopamine receptors in human basilar arteries

Area of Science:

• Pharmacology
• Neuroscience
• Vascular Biology

Background:

• Dopamine's role in vascular tone regulation is complex.
• Understanding dopamine receptor subtypes in cerebral arteries is crucial for treating cerebrovascular disorders.

Purpose of the Study:

• To characterize the dopamine receptors mediating relaxation in the human basilar artery.
• To compare these receptors with those in other vascular beds.

Main Methods:

• Isolated human basilar artery strips were contracted with prostaglandin F2 alpha (PGF2 alpha).
• Concentration-dependent effects of dopamine and its analogues were assessed.
• Pharmacological antagonism using various dopamine receptor blockers was employed.

Main Results:

• Dopamine induced significant, concentration-dependent relaxation of contracted human basilar artery strips.
• Specific dopamine receptor agonists (apomorphine, 6,7-ADTN, SK&F 38393) mimicked this effect.
• Certain antagonists (e.g., butaclamol, flupenthixol) competitively blocked dopamine's relaxant action, while others (e.g., sulpiride) were ineffective.

Conclusions:

• The human basilar artery possesses dopamine receptors that mediate smooth muscle relaxation.
• These receptors are pharmacologically similar to dopamine receptors in rabbit mesenteric/splenic arteries and dog renal/mesenteric arteries.
• The identified receptors differ from presynaptic dopamine receptors on sympathetic nerve terminals.