Characterization of strychnine-sensitive glycine receptors in acutely isolated adult rat basolateral amygdala neurons.
Large concentrations of the beta-amino acid, taurine, can be found in many forebrain areas such as the basolateral amygdala, a portion of the limbic forebrain intimately associated with the regulation of fear/anxiety-like behaviors. In addition to its cytoprotective and osmoregulatory roles, taurine may also serve as an agonist at GABA(A)- and strychnine-sensitive glycine receptors. In this latter context, the present study demonstrates that application of taurine to acutely isolated neurons from the basolateral amygdala of adult rats causes significant alterations in resting membrane current, as measured by whole-cell patch clamp electrophysiology. Using standard pharmacological approaches, we find that currents gated by concentrations of taurine </=3 mM are predominantly mediated by strychnine-sensitive receptors. Furthermore, these strychnine-sensitive receptors are shown to be pharmacologically and biophysically similar to 'classic' strychnine-sensitive, chloride-conducting glycine receptors expressed in brainstem and spinal cord. While amygdala glycine receptors can be distinguished from GABA(A) receptors expressed by the same neurons, these two chloride channels are functionally expressed at comparable levels. Given that a number of clinically relevant compounds are associated with the regulation of GABA(A) receptors in this brain region, the presence of both strychnine-sensitive glycine receptors and their agonist, taurine, in the basolateral amygdala may suggest an important role for these receptors in the limbic forebrain of adult rats.
McCool
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BA
Department of Medical Pharmacology, Texas A&M University System Health Science Center, 368 Reynolds Building, College Station, TX, USA. mccool@medicine.tamu.edu
Botting
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SK
D000679:Amygdala / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D018929:Cell Culture Techniques; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism; D018009:Receptors, Glycine / Q000187:drug effects* / Q000378:metabolism*; D013331:Strychnine / Q000494:pharmacology*; D013654:Taurine / Q000378:metabolism* / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D018118:Chloride Channels; D011963:Receptors, GABA-A; D018009:Receptors, Glycine; D013654:Taurine; D005680:gamma-Aminobutyric Acid; D013331:Strychnine; D005998:Glycine