The distribution and function of gamma-aminobutyric acid (GABA) in the superior colliculus.

摘要: Laminer analysis of the distribution GABA and GAD in superior colliculus has shown that pattern within SC is similar rabbit, cat, guinea pig. The highest levels were found superficial gray layer (SGL), averaging 37-40 mmol/kg dry weight. concentrations deep layers each only half SGL. both upper SGL are same as those substantia nigra medial forebrain bundle which have amounts CNS. Denervation studies fibers projecting to suggest concentrated intrinsic layer. results obtained from immunohistochemical electron microscopic on localization neurons corresponds well with regional reported here. However, pharmacological electrophysiological do not necessarily accord because they indicate there many sensitive DGL. To investigate role SGL, effect its agonists antagonists neurotransmission been studied slices a perfusion system. Bath applied (100 microM 1 mM) enhanced amplitude postsynaptic field potentials (PSP) dose-dependent fashion at above mM it depressed PSP fashion. A response was muscimol (0.1-10 excitation; greater than 10 inhibition). However (-)-baclofen inhibited PSP. Bicuculline (1 microM) shifted dose-response inhibitory curve right, while excitatory enhanced. These an action nigro-tectal GABAergic terminate intermediate SC. Inhibition activity causes irrepressible saccades made toward center movement activation delays slows saccadic eye movements. Thus, plays important control projection also related propagation generalized seizures. There exist collicular suppress seizures.(ABSTRACT TRUNCATED AT 400 WORDS)