The effects of alpha-human atrial natriuretic peptide and milrinone on pial vessels during blood-brain barrier disruption in rabbits.
The effects of alpha-human atrial natriuretic peptide (HANP) and milrinone on cerebral pial vessels, especially during blood-brain barrier (BBB) disruption, are not clear. We studied topical HANP (10(-14), 10(-12), and 10(-10) M) or milrinone (10(-7), 10(-5), and 10(-3) M), and IV HANP (0.1, 0.2, and 1.0 microg. kg(-1). min(-1)) or milrinone (0.5, 5.0, and 20.0 microg. kg(-1). min(-1)) with or without hyperosmolar BBB disruption, using a rabbit cranial window preparation. At 10(-12) and 10(-10) M topical HANP produced significant arteriolar (16%, 20%, respectively), but no venular dilation. Topical milrinone (10(-3) M) produced significant arteriolar and venular dilation (21%, 8%, respectively). IV HANP produced no arteriolar or venular changes at any dose except during BBB disruption, when it caused a significant arteriolar (16%, 16%, and 17%, respectively), but no venular dilation. In contrast, IV milrinone caused small but significant arteriolar and venular dilation without BBB disruption (arterioles, 6%, 7% and 8%, respectively; venules, 6% at 20.0 microg. kg(-1). min(-1)). During BBB disruption, these responses to milrinone were similar. Although HANP and milrinone each have a direct vasodilator effect on arterioles, their systemic administration at clinical doses could induce different effects. BBB disruptive conditions could increase the response of pial vessels to systemically administered HANP.


CONCLUSIONS
Although alpha-human atrial natriuretic peptide (HANP) and milrinone each have a direct vasodilator effect on cerebral pial arterioles, their systemic administration at clinical doses could have different effects and blood-brain-barrier disruptive conditions could alter the response of pial vessels to HANP, but not to milrinone.
Iida
H
H
Department of Anesthesiology and Critical Care Medicine, ifu University School of Medicine, Gifu City, Gifu, Japan. iida@cc.gifu-u.ac.jp
Iida
M
M
Takenaka
M
M
Oda
A
A
Uchida
M
M
Fujiwara
H
H
Dohi
S
S
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000502:physiology*; D002550:Cerebral Veins / Q000187:drug effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007262:Infusions, Intravenous; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D020105:Milrinone / Q000494:pharmacology*; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology
D011994:Recombinant Proteins; D009320:Atrial Natriuretic Factor; D020105:Milrinone