Clonidine reduces substance P binding in rat spinal cord membrane preparation.
The effects of clonidine on substance P (SP) binding was investigated using rat brain and spinal cord membrane preparations preincubated with various concentrations of clonidine. [3H]SP specific binding in the spinal cord was significantly decreased with 10(-4) M clonidine, but no effect on binding was seen in the brain. Scatchard analysis of SP binding indicated that Bmax was significantly depressed without changing the affinity. The mechanism of clonidine-induced analgesia includes a spinal neural component and action on the SP receptors.
Hama
A T
AT
Department of Pharmacology, Hiroshima University School of Medicine, Japan.
Nakata
Y
Y
Segawa
T
T
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013373:Substance P / Q000378:metabolism*
D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013373:Substance P; D003000:Clonidine