TY - JOUR
T1 - Different roles of PKC and MAP kinases in arteriolar constrictions to pressure and agonists
AU - Massett, Michael P.
AU - Ungvari, Zoltan
AU - Csiszar, Anna
AU - Kaley, Gabor
AU - Koller, Akos
PY - 2002/12/1
Y1 - 2002/12/1
N2 - Protein kinase C (PKC) and mitogen-activated protein (MAP) kinases have been implicated in the modulation of agonist-induced contractions of large vessels. However, their role in pressure- and agonist-induced constrictions of skeletal muscle arterioles, which have a major role in regulating peripheral resistance, is not clearly elucidated. Thus constrictions of isolated rat gracilis muscle arterioles (∼80 μm in diameter) to increases in intraluminal pressure and to norepinephrine (NE) or angiotensin II (ANG II) were assessed in the absence or presence of chelerythrine, PD-98058, and SB-203580 (inhibitors of PKC, p42/44 and p38 MAP kinase pathways, respectively). Arteriolar constriction to NE and ANG II were significantly reduced by chelerythrine (by ∼90%) and unaffected by SB-203580, whereas PD-98058 decreased only ANG II-induced constrictions (by -60%). Pressure-induced increases in wall tension (from 0.1 to 0.7 N/m) resulted in significant arteriolar constrictions (50% maximum) that were abolished by chelerythrine without altering smooth muscle intracellular Ca2+ concentration ([Ca2+]i) (fura 2 microfluorimetry). PD-98058 and SB-203580 significantly decreased the magnitude of myogenic tone (by 20% and 60%, respectively) and reduced the sensitivity of the myogenic mechanism to wall tension, causing a significant rightward shift in the wall tension-myogenic tone relationship without affecting smooth muscle [Ca2+i]. MAP kinases were demonstrated with Western blotting. Thus in skeletal muscle arterioles 1) PKC is involved in both myogenic and agonist-induced constrictions, 2) PD-98058-sensitive p42/44 MAP kinases modulate both wall tension-dependent and ANG II-induced constrictions, whereas 3) a SB-203580-sensitive p38 MAP kinase pathway seems to be specifically involved in the mechanotransduction of wall tension.
AB - Protein kinase C (PKC) and mitogen-activated protein (MAP) kinases have been implicated in the modulation of agonist-induced contractions of large vessels. However, their role in pressure- and agonist-induced constrictions of skeletal muscle arterioles, which have a major role in regulating peripheral resistance, is not clearly elucidated. Thus constrictions of isolated rat gracilis muscle arterioles (∼80 μm in diameter) to increases in intraluminal pressure and to norepinephrine (NE) or angiotensin II (ANG II) were assessed in the absence or presence of chelerythrine, PD-98058, and SB-203580 (inhibitors of PKC, p42/44 and p38 MAP kinase pathways, respectively). Arteriolar constriction to NE and ANG II were significantly reduced by chelerythrine (by ∼90%) and unaffected by SB-203580, whereas PD-98058 decreased only ANG II-induced constrictions (by -60%). Pressure-induced increases in wall tension (from 0.1 to 0.7 N/m) resulted in significant arteriolar constrictions (50% maximum) that were abolished by chelerythrine without altering smooth muscle intracellular Ca2+ concentration ([Ca2+]i) (fura 2 microfluorimetry). PD-98058 and SB-203580 significantly decreased the magnitude of myogenic tone (by 20% and 60%, respectively) and reduced the sensitivity of the myogenic mechanism to wall tension, causing a significant rightward shift in the wall tension-myogenic tone relationship without affecting smooth muscle [Ca2+i]. MAP kinases were demonstrated with Western blotting. Thus in skeletal muscle arterioles 1) PKC is involved in both myogenic and agonist-induced constrictions, 2) PD-98058-sensitive p42/44 MAP kinases modulate both wall tension-dependent and ANG II-induced constrictions, whereas 3) a SB-203580-sensitive p38 MAP kinase pathway seems to be specifically involved in the mechanotransduction of wall tension.
KW - Microvessels
KW - Mitogen-activated protein
KW - Myogenic constriction
KW - PD-98059
KW - Protein kinase C
KW - SB-203580
KW - Smooth muscle
UR - http://www.scopus.com/inward/record.url?scp=0036890302&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00544.2002
DO - 10.1152/ajpheart.00544.2002
M3 - Article
C2 - 12427592
AN - SCOPUS:0036890302
SN - 0363-6135
VL - 283
SP - H2282-H2287
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 6 52-6
ER -