Clonidine-induced rhythmic activity in rabbit anococcygeus muscle

Nahid Radjaee-Behbahani; Ahmad Reza Dehpour; Emadeddin Tajkhorshid; Kolsoum Kheirollahi

doi:10.1016/0306-3623(95)00101-8

Clonidine-induced rhythmic activity in rabbit anococcygeus muscle

Nahid Radjaee-Behbahani
, Ahmad Reza Dehpour
, Emadeddin Tajkhorshid
, Kolsoum Kheirollahi

Research output: Contribution to journal › Article › peer-review

Abstract

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.

Original language	English (US)
Pages (from-to)	525-528
Number of pages	4
Journal	General Pharmacology: The Vascular System
Volume	27
Issue number	3
DOIs	https://doi.org/10.1016/0306-3623(95)00101-8
State	Published - Apr 1996
Externally published	Yes

Keywords

Calcium
Calcium channel blockers
Rabbit anococcygeus muscle
Rhythmic activity

ASJC Scopus subject areas

Pharmacology

Online availability

10.1016/0306-3623(95)00101-8

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title = "Clonidine-induced rhythmic activity in rabbit anococcygeus muscle",

abstract = "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.",

keywords = "Calcium, Calcium channel blockers, Rabbit anococcygeus muscle, Rhythmic activity",

author = "Nahid Radjaee-Behbahani and Dehpour, \{Ahmad Reza\} and Emadeddin Tajkhorshid and Kolsoum Kheirollahi",

year = "1996",

month = apr,

doi = "10.1016/0306-3623(95)00101-8",

language = "English (US)",

volume = "27",

pages = "525--528",

journal = "General Pharmacology: The Vascular System",

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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

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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: The Vascular System

JF - General Pharmacology: The Vascular System

IS - 3

ER -

Clonidine-induced rhythmic activity in rabbit anococcygeus muscle

Abstract

Keywords

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