1. The isolated, intact heart of the marine arachnid Limulus polyphemus continues to beat in vitro for many hours. Application of ^aminobutyric acid (GABA) decreased the heart beat frequency with a threshold of 3xlO~ 7 moir 1 and an EC50 of 2.0±0.6xlO"moll" (mean±s.D., N = 8). At lO^mol l" 1 and above the heart beat was completely and reversibly inhibited. 2. The agonist potency profile of the ...

In the hippocampus, the inhibitory neurotransmitter GABA shapes the activity of the output pyramidal neurons and plays important role in cognition. Most of its inhibitory effects are mediated by signaling from GABAB receptor to the G protein-gated Inwardly-rectifying K+ (GIRK) channels. Here, we show that RGS7, in cooperation with its binding partner R7BP, regulates GABABR-GIRK signaling in hip...

The phrenic nucleus was identified by microinjections of N-methyl-d-aspartic acid in urethan-anesthetized adult male Wistar rats. Microinjections of GABAA and GABAB receptor agonists (muscimol and baclofen, respectively) at the same site decreased the phrenic nerve burst amplitude. Microinjections of GABAA and GABAB receptor antagonists (bicuculline and 2-hydroxysaclofen, respectively) blocked ...

INTRODUCTION y-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian brain. It mediates its effects via the specific interaction with the integral membrane proteins, the GABA receptors. GABA receptors can be classified according to their respective transduction mechanisms following activation, as the GABA and the GABAB receptor respectively. The focus of this review...