ABSTRACT

Glycine is taken up twice as rapidly by neurons R3-R14 as by other identified neurons in the Aplysia parietovisceral ganglion.  Earlier studies had shown that R3-R14 have much higher glycine concentrations than other Aplysia neurons.  Most of the glycine taken up by R3-R14 was biochemically untransformed for at least 1 h following its uptake.  Glycine is actively transported into R3-R14 and other Aplysia neurons by carrier-mediated processes.  Glycine uptake by R3-R14 was markedly reduced in the absence of Na+ and in the presence of Hg2+, while these treatments had little effect on glycine uptake by other Aplysia neurons.  There appears to be a special glycine uptake system present in R3-R14 and a general glycine uptake system common to all Aplysia neurons.  The elevated glycine concentrations and special glycine uptake associated with R3-R14 may indicate that glycine is utilized as a neurotransmitter by those neurons.


Thomas M. Iliffe, Department of Marine Biology, Texas A&M University at Galveston, P.O. Box 1675, Galveston, Texas 77553, USA.
E-mail: iliffet@tamug.edu

Keywords:  glycine, Aplysia, biochemestry, neurons.