Intrathecal administration of yohimbine impairs locomotion in intact rats.
The effects of upper lumbar level intrathecal injection of yohimbine, an alpha2-noradrenergic antagonist, on overground locomotion in intact rats was studied. This treatment caused dose-dependent impairment of hindlimb locomotor movement, which varied from transient hindlimb paralysis at a dose of 200 microg/20 microl to transient trunk instability at 50 microg/20 microl. Repetitive (every 48 h) injections of yohimbine at high (200 microg/20 microl) and medium (100 microg/20 microl) doses caused tachyphylaxis, which usually led to a lack of reaction to the third injection. This phenomenon was not observed after repetitive injections of the low (50 microg/20 microl) dose of the drug. These results show that the noradrenergic system is involved in the control of locomotion, since intrathecal administration of a specific antagonist affects this activity in intact rats.
Majczyński
Henryk
H
Department of Neurophysiology, Nencki Institute of Experimental Biology, 3 Pasteura Str., 02-093 Warsaw, Poland. h.majczynski@nencki.gov.pl
Cabaj
Anna
A
Sławińska
Urszula
U
Górska
Teresa
T
D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006614:Hindlimb / Q000187:drug effects; D007278:Injections, Spinal; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology; D008159:Lumbar Vertebrae; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology; D013618:Tachyphylaxis / Q000502:physiology; D015016:Yohimbine / Q000008:administration & dosage*
D000317:Adrenergic alpha-Antagonists; D015016:Yohimbine