DISTRIBUTION OF ADENOSINE-A1-RECEPTORS IN PRIMARY VISUAL-CORTEX OF DEVELOPING AND ADULT MONKEYS

Adenosine is an endogenous neuromodulator, whose actions in the brain are mediated by several, highly specific receptor systems. This study examined the distribution of adenosine Al receptors in the primary vis ual cortex of developing and adult monkeys by way of radioligand-bindi ng autoradiography. Receptor density was found to be highest in layers 2/3 and 5 of adult striate cortex and lowest in layer 4. A similar pa ttern was found in infant monkeys that were in the critical period of development. Furthermore, removal of visual stimulation appeared to ha ve no effect on receptor density in any of the layers. These results s how that levels of adenosine Al receptors are not affected within ocul ar dominance columns after removal of visual input and that the genicu lorecipient layer is less likely to be influenced by endogenous adenos ine than other layers during early development and in the adult.