Localization of Sensitive Sites to Taurine, Γ‐aminobutyric Acid, Glycine and Β‐alanine in the Molecular Layer of Guinea‐pig Cerebellar Slices

Abstract

1 The localization, in the molecular layer of guinea-pig cerebellar slices, of the sites most sensitive to iontophoretically applied taurine, y-aminobutyric acid (GABA), glycine and P-alanine was investigated. 2 The most sensitive sites were located (expressed as the distance from the Purkinje cell body to the pial surface): 0 rm, 60 pm and 220 pm for taurine; 0 ptm and 180 psm for GABA; 80 tm and 200 pm for glycine, and 80 pm, 180 pm and 300 j.m for /-alanine. 3 The sensitive site (at 0 pm) to GABA was considered to represent the basket synapses on the Purkinje cell soma, while the sites (60 to 80 pm and 200 to 300 pm) for taurine, glycine and /-alanine were tentatively assigned to the synapses of the stellate neurones on the Purkinje cell dendrites. 4 Inhibitory actions of all four amino acids tested at the most sensitive sites were antagonized by both picrotoxin and strychnine. 5 The possibility that taurine might be the neurotransmitter of the stellate neurones in guinea-pig cerebellum is discussed.

Colocalization of taurine- and cysteine sulfinic acid decarboxylase- like immunoreactivity in the cerebellum of the rat with monoclonal antibodies against taurine

“…Studies have suggested that taurine acts as a neurotransmitter for stellate intemeurons in the cerebellum (Nadi et al, 1977;Frederickson et al, 1978;McBride and Frederickson, 1980;Okamoto and Sakai, 1980;Okamoto et al, 1983a-c). Some anatomical studies report tritiated taurine uptake into cerebellar intemeurons (Chan-Palay et al, 1982a) and CSADC-LI in the same intemeurons; i.e., Golgi, stellate, and basket cells (ChanPalay et al, 1982a, b).…”

“…Taurine is more effective at causing hyperpolarization on the Purkinje cell dendrite than on the soma (Frederickson et al, 1978;Okamoto and Sakai, 1980;Okamoto et al, 1983a, b). Calcium is the ion primarily responsible for dendritic excitability in Purkinje cells (Llinb and Sugimori, 1980).…”

“…Changes in taurine concentration occur in dominantly inherited cerebellar atrophies such as olivopontocerebellar atrophy (Perry, 1978) and may be significant in Friedreich's ataxia (Barbeau et al, 1982). Several studies suggest that taurine et al -Taurine and CSADC Colocalization i n Rat Cerebellum may be used by stellate interneurons in the cerebellum as a neurotransmitter (Nadi et al, 1977;Frederickson et al, 1978;McBride and Frederickson, 1980;Okamoto and Sakai, 1980;Okamoto et al, 1983~). sera raised against taurine conjugated to carrier proteins.…”

Contribution of cerebellar intracortical inhibition to Purkinje cell response during vestibulo‐ocular reflex of alert rabbits.

“…Bicuculline also antagonizes action of the taurine (Okamoto & Quastel, 1976), which has been proposed as a transmitter of stellate cells (McBride, Nadi, Altman & Aprison, 1976;Frederickson, Neuss, Morzorati & McBride, 1978). However, both the axon terminals of stellate cells and the taurine-sensitive sites are distributed fairly distally on Purkinje cell dendrites (Eccles et al 1967;Okamoto & Sakai, 1980). Since the tips of the micro-electrodes in the present experiments were positioned so that ionophoretic ejection of GABA evoked maximal inhibition of each Purkinje cell, it is likely that they were near the somatic area of the Purkinje cells, where GABA sensitivity is highest (Okamoto & Sakai, 1980).…”

“…However, both the axon terminals of stellate cells and the taurine-sensitive sites are distributed fairly distally on Purkinje cell dendrites (Eccles et al 1967;Okamoto & Sakai, 1980). Since the tips of the micro-electrodes in the present experiments were positioned so that ionophoretic ejection of GABA evoked maximal inhibition of each Purkinje cell, it is likely that they were near the somatic area of the Purkinje cells, where GABA sensitivity is highest (Okamoto & Sakai, 1980). Therefore, ionophoretically applied bicuculline might act on the Purkinje cells by blocking the inhibitory action of the basket cells that is exerted at the Purkinje cell soma (Eccles et al 1967) rather than by blocking the action of the stellate cells.…”