E. Bouskela et Fzga. Cyrino, EFFECTS OF BUFLOMEDIL ON SPONTANEOUS VASOMOTION AND MEAN ARTERIOLAR INTERNAL DIAMETER IN THE HAMSTER-CHEEK POUCH, Journal of vascular research, 31(5), 1994, pp. 287-294
Citations number
28
Categorie Soggetti
Hematology,"Medicine, General & Internal",Physiology
Intravital microscopy of the hamster cheek pouch microvasculature was
used for in vivo studies on the effects of buflomedil, phentolamine (a
lpha-adrenergic receptor antagonist) and norepinephrine on the mean in
ternal arteriolar diameter and spontaneous vasomotion. All drugs were
applied topically. The vaso-motor activity was studied in 125 arteriol
es (internal diameter range 18.0-62.0 mu m) of 34 preparations. Additi
on of buflomedil (10(-9) to 10(-5) M) did not affect the arteriolar di
ameter significantly(from 100.7 +/- 3.5 to 106.4 +/- 1.8%, values expr
essed in percent of the initial diameter as mean +/- SE), but increase
d the vasomotion frequency and amplitude by approximately 20% (from 7.
5 +/- 0.3 to 9.2 +/- 0.2 cpm) and 30% (from 7.3 +/- 0.3 to 10.0 +/- 0.
5 mu m), respectively. Phentolamine (10(-9) to 10(-5) M) dose-dependen
tly increased the microvascular diameter (from 102.3 +/- 1.2 to 139.1
+/- 4.3%) and reduced the vasomotion frequency and amplitude (from 8.0
+/- 0.3 to 1.9 +/- 0.5 cpm and from 9.0 +/- 2.1 to 3.1 +/- 0.2 mu m,
respectively). Addition of buflomedil (10(-7) M) reduced the vasodilat
ion evoked by phentolamine (from 103.3 +/- 0.7 to 127.0 +/- 1.5%) and
potentiated its depressive effect on vaso-motion frequency and amplitu
de (from 7.6 +/- 0.1 to 1.0 +/- 0.3 cpm and from 9.0 +/- 0.3 to 1.9 +/
- 0.6 mu m, respectively). Norepinephrine (10(-9) to 10(-5) M) dose-de
pendently decreased to arteriolar diameter (from 102.3 +/- 0.7 to 69.6
+/- 1.6%) and the vasomotion frequency and amplitude (from 8.4 +/- 0.
2 to 0.4 +/- 0.3 cmp and from 8.7 +/- 0.2 to 0.5 +/- 0.4 mu m, respect
ively). Addition of buflomedil (10(-7) M) reduced the vasoconstriction
elicited by norepinephrine (from 103.2 +/- 0.9 to 82.9 +/- 3.9%) and
restored the vasomotion frequency and amplitude (from 8.4 +/- 0.3 to 7
.8 +/- 0.4 cpm and from 8.6 +/- 0.2 to 7.8 +/- 0.3 mu m, respectively)
. The effects observed with buflomedil on the hamster cheek pouch micr
ocirculation suggest a direct action on the smooth muscle excitability
and further support its properties as a competitive inhibitor of alph
a-adrenergic receptors and as a weak calcium antagonist.