Abstract
Ionotropic gamma-aminobutyric acid (GABA) receptors are known to mediate excitation in neonatal neurones as a crucial developmental factor. In the present study we employed calcium imaging techniques with the calcium indicator Fura-2-AM to study the pharmacology of GABA-induced calcium responses in cultures prepared from neonatal rat superficial superior colliculus (SC), after immunocytochemical labelling confirmed the presence of GABA(C) rho(1) subunits in 35% of neurones. Rises in neuronal intracellular calcium were obtained in response to GABA and also to the subtype-specific GABA(A) agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol. However, the GABA(C) agonist cis-4-aminocrotonic acid induced calcium response only at unspecifically high concentrations (500 muM). Co-application of GABA antagonists revealed that both GABA(A&C) agonists' actions could be blocked by the GABA(A) antagonist bicuculline but not the GABA(C) antagonists 1,2,5,6-tetrahydro-(pyridin-4-yl) methylphosphinic acid. This suggests that activation of GABA(A) but not GABA(C) receptors contributes to excitatory GABA responses and related calcium signals in neonatal SC neurones. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 79-82 |
| Number of pages | 3 |
| Journal | Neuroscience Letters |
| Volume | 334 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2002 |
Keywords
- superior colliculus
- calcium imaging
- gamma-aminobutyric acid(C)
- cis-4-aminocrotonic acid
- 1,2,5,6-tetrahydro-(pyridin-4-yl) methylphosphinic acid
- excitation
- neonatal
- development
- GABA(C) RECEPTORS
- HIPPOCAMPAL-NEURONS
- EXPRESSION
- SUBUNIT
- RHO-1
- BRAIN