TY - JOUR
T1 - Clonidine-induced rhythmic activity in rabbit anococcygeus muscle
AU - Radjaee-Behbahani, Nahid
AU - Dehpour, Ahmad Reza
AU - Tajkhorshid, Emadeddin
AU - Kheirollahi, Kolsoum
PY - 1996/4
Y1 - 1996/4
N2 - 1. Clonidine 0.5 mM induced an extremely regular rhythmic activity in isolated rabbit anococcygeus muscle. The movements were resistant to tetrodotoxin effect. 2. Prazosin (5×10-8M-5×10-6M) and yohimbine (1.5×10-7M-5×10-4M) showed no remarkable effect on clonidine-induced rhythmic activity. 3. The clonidine-induced contractions were dependent on extracellular calcium and could be inhibited by the omission of calcium from medium or the introduction of verapamil (IC50=1.3×10-7M) or nifedipine (IC50=7.5×10-8M). 4. Pretreatment of animals with reserpine made the preparations 2800-fold more sensitive to this action of clonidine. 5. It can be concluded from this study that clonidine is able to induce rhythmic activity in rabbit anococcygeus muscle through a mechanism that increases intracellular concentration of Ca++ via membrane calcium channels.
AB - 1. Clonidine 0.5 mM induced an extremely regular rhythmic activity in isolated rabbit anococcygeus muscle. The movements were resistant to tetrodotoxin effect. 2. Prazosin (5×10-8M-5×10-6M) and yohimbine (1.5×10-7M-5×10-4M) showed no remarkable effect on clonidine-induced rhythmic activity. 3. The clonidine-induced contractions were dependent on extracellular calcium and could be inhibited by the omission of calcium from medium or the introduction of verapamil (IC50=1.3×10-7M) or nifedipine (IC50=7.5×10-8M). 4. Pretreatment of animals with reserpine made the preparations 2800-fold more sensitive to this action of clonidine. 5. It can be concluded from this study that clonidine is able to induce rhythmic activity in rabbit anococcygeus muscle through a mechanism that increases intracellular concentration of Ca++ via membrane calcium channels.
KW - Calcium
KW - Calcium channel blockers
KW - Rabbit anococcygeus muscle
KW - Rhythmic activity
UR - https://www.scopus.com/pages/publications/0030000120
UR - https://www.scopus.com/pages/publications/0030000120#tab=citedBy
U2 - 10.1016/0306-3623(95)00101-8
DO - 10.1016/0306-3623(95)00101-8
M3 - Article
C2 - 8723538
AN - SCOPUS:0030000120
SN - 0306-3623
VL - 27
SP - 525
EP - 528
JO - General Pharmacology: Vascular System
JF - General Pharmacology: Vascular System
IS - 3
ER -