Clonidine stimulated the release of dynorphin in the spinal cord of the rat: a possible mechanism for its depressor effects.
The decrease in blood pressure, heart rate and sympathetic nervous discharges (SND) induced by intrathecal injection of clonidine (1 microgram) in the rat was prevented by pretreatment with intrathecal injection of an antiserum against dynorphin. Clonidine (10(-4) M) added to the artificial cerebrospinal fluid perfusing the spinal subarachnoid space of the rat increased the amount of immunoreactive dynorphin in the perfusate. Intrathecal injection of dynorphin (30 micrograms) caused hypotension, bradycardia and a reduction in SND. These results suggest that the release of dynorphin in the spinal cord may constitute one of the mechanisms for the depressor effects of clonidine.
Xie
C W
CW
Tang
J
J
Han
J S
JS
D000818:Animals; D001696:Biomechanical Phenomena; D001794:Blood Pressure / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology*; D004399:Dynorphins / Q000276:immunology / Q000378:metabolism*; D006339:Heart Rate / Q000187:drug effects*; D007106:Immune Sera / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000502:physiology
D007106:Immune Sera; D004399:Dynorphins; D003000:Clonidine