Back to Search
Start Over
Purinergic modulation in the development of the rat uncrossed retinotectal pathway.
- Source :
-
Neuroscience [Neuroscience] 2009 Nov 10; Vol. 163 (4), pp. 1061-8. Date of Electronic Publication: 2009 Jul 18. - Publication Year :
- 2009
-
Abstract
- Adenosine is a neuromodulator implicated in nervous system development and plasticity and its effects are mediated by inhibitory (A(1), A(3)) and excitatory (A(2a), A(2b)) receptors. The role of adenosine in the synaptic activity depends mainly on a balanced activation of A(1) and A(2a) receptors which are activated by various ranges of adenosine concentrations. Herein, we investigated the expression of A(1) and A(2a) receptors and also the accumulation of cAMP in the superior colliculus at different stages of development. Furthermore, we examined the effects of an acute in vivo blockade of adenosine deaminase during the critical period when the elimination of misplaced axons/terminals takes place with a simultaneous fine tuning of terminal arbors into appropriate terminal zones. Lister Hooded rats ranging from postnatal days (PND) 0-70 were used for ontogeny studies. Our results indicate that A(1) expression in the visual layers of the superior colliculus is higher until PND 28, while A(2a) expression increases after PND 28 in a complementary developmental pattern. Accordingly, the incubation of collicular slices with 5'-N-ethylcarboxamido-adenosine, a non-specific adenosine receptor agonist, showed a significant reduction in cAMP accumulation at PND 14 and an increase in adults. For the anatomical studies, the uncrossed retinotectal projections were traced after the intraocular injection of horseradish peroxidase. One group received daily injections of an adenosine deaminase inhibitor (erythro-9(2-hydroxy-3-nonyl adenine), 10 mg/kg i.p.) between PND 10 and 13, while control groups were treated with vehicle injections (NaCl 0.9%, i.p.). We found that a short-term blockade of adenosine deaminase during the second postnatal week induced an expansion of retinotectal terminal fields in the rostrocaudal axis of the tectum. Taken together, the results suggest that a balance of purinergic A(1) and A(2a) receptors through cAMP signaling plays a pivotal role during the development of topographic order in the retinotectal pathway.
- Subjects :
- Adenine analogs & derivatives
Adenine pharmacology
Adenosine A1 Receptor Agonists
Adenosine A2 Receptor Agonists
Adenosine Deaminase Inhibitors
Adenosine-5'-(N-ethylcarboxamide) pharmacology
Animals
Animals, Newborn
Central Nervous System Agents pharmacology
Enzyme Inhibitors pharmacology
Horseradish Peroxidase
Neuronal Tract-Tracers
Rats
Rats, Inbred Strains
Retina anatomy & histology
Retina drug effects
Superior Colliculi anatomy & histology
Superior Colliculi drug effects
Visual Pathways anatomy & histology
Visual Pathways drug effects
Visual Pathways growth & development
Cyclic AMP metabolism
Receptor, Adenosine A1 metabolism
Receptor, Adenosine A2A metabolism
Retina growth & development
Superior Colliculi growth & development
Subjects
Details
- Language :
- English
- ISSN :
- 1873-7544
- Volume :
- 163
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 19619617
- Full Text :
- https://doi.org/10.1016/j.neuroscience.2009.07.029