RT Journal Article
SR Electronic
T1 Selectivity of the effects of guanosine-5'-O-(2-thiodiphosphate) on agonist inhibition of the M-current in amphibian sympathetic neurons
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2130
OP 2134
DO 10.1523/JNEUROSCI.11-07-02130.1991
VO 11
IS 7
A1 Simmons, MA
A1 Mather, RJ
YR 1991
UL http://www.jneurosci.org/content/11/7/2130.abstract
AB In bullfrog sympathetic neurons, luteinizing hormone-releasing hormone, muscarine, and substance P act as agonists at specific membrane receptors to decrease a potassium current, IM. The receptors are coupled to guanine nucleotide-binding proteins (G-proteins). Whole-cell recordings of IM were made from isolated bullfrog sympathetic neurons to examine the effects of intracellularly applied guanosine-5′-O-(2- thiodiphosphate) (GDP beta S) on agonist inhibition of IM. Successive responses to a given agonist were decreased in the presence of GDP beta s. Subsequent responses to the other agonists were then measured to determine the degree of overlap of the effect of GDP beta S for the different agonists. GDP beta S selectively inhibited successive responses to one agonist such that a subsequent application of a different agonist was still effective. If GDP beta S acts at the level of the G-protein, this suggests that each receptor is coupled to a separate population of G-proteins. Alternatively, GDP beta S may act at the receptor level to block receptor coupling to IM.