Noradrenergic alpha-1 and alpha-2 antagonists block L-dopa-induced air-stepping in neonatal rats.
Five-day-old rat pups suspended in air and administered L-3,4-dihydroxyphenylalanine (L-DOPA) engage in a highly stereotyped and coordinated locomotor behavior termed air-stepping. L-DOPA is a precursor for dopamine and noradrenaline and one or both of these neurotransmitters could play a role in L-DOPA-induced air-stepping. The role of noradrenaline was investigated by assessing the abilities of the alpha-1 noradrenergic receptor antagonist prazosin and the alpha-2 noradrenergic receptor antagonist idazoxan to block L-DOPA-induced air-stepping in 5-day-old rats. Both antagonists decreased the duration of air-stepping. In addition, prazosin altered the topography of air-stepping by interfering with coordination of the hindlimbs. The results suggest that alpha-1 and alpha-2 noradrenergic receptor subtypes are involved in L-DOPA-induced air-stepping.
Taylor
L L
LL
Department of Psychology, University of Florida, Gainesville 32611.
Sickles
A E
AE
Stehouwer
D J
DJ
Van Hartesveldt
C
C
D058668:Adrenergic alpha-1 Receptor Antagonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D004146:Dioxanes / Q000494:pharmacology; D005260:Female; D019329:Idazoxan; D007980:Levodopa / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008297:Male; D009638:Norepinephrine / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013239:Stereotyped Behavior / Q000187:drug effects / Q000502:physiology*
D058668:Adrenergic alpha-1 Receptor Antagonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D007980:Levodopa; D009638:Norepinephrine; D011224:Prazosin; D019329:Idazoxan