Effects of bilateral injection of GABA into the substantia nigra on spontaneous behavior and measures of analgesia.
Bilateral injection of gamma-aminobutyric acid (GABA, 10-300 micrograms) into the substantia nigra (pars reticulata) of rats produced stereotyped sniffing and had an analgesic-like effect on the hot-plate but not on the tail-flick test. These effects of GABA (30 micrograms) were suppressed by simultaneous administration of a sub-convulsant dose of bicuculline methiodide (100 ng). Significant increases in locomotion occurred when GABA (300 micrograms) was injected along with the inhibitor of GABA-transaminase, d,l-gamma-vinyl-GABA (GVG; 5 micrograms) and the inhibitor of the uptake of GABA, 1-2,4-diaminobutyric acid (DABA; 5 micrograms). No other behavioral effects were observed following injection of GABA into the nigra, either alone or in combination with GVG and DABA. Bilateral injection of bicuculline (100-600 ng) into the nigra had strong convulsant actions. When injected simultaneously with bicuculline, GABA reduced bicuculline-induced seizures. These results are discussed in terms of their relevance to understanding the mechanisms that underlie the behavioral effects produced by injection of muscimol into the nigra.
Baumeister
A A
AA
Department of Psychology, Louisiana State University, Baton Rouge 70803.
Hawkins
M F
MF
Anderson-Moore
L L
LL
Anticich
T G
TG
Higgins
T D
TD
Griffin
P
P
D000698:Analgesia; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001640:Bicuculline / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007267:Injections; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D013239:Stereotyped Behavior / Q000187:drug effects; D013378:Substantia Nigra; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000494:pharmacology*
D005680:gamma-Aminobutyric Acid; D001640:Bicuculline