RESUMEN
Long-lasting increases in REM sleep are induced in the rat following injection of small amounts of muscarinic receptor agonists into the caudal oral pontine reticular formation. By injecting carbachol at the beginning of the light period or beginning of the dark period, we sought to determine whether the muscarinic, REM sleep induction is influenced by the time of day it is initiated. We found that carbachol is more effective at increasing REM sleep when administered at the beginning of the dark in 87% of the cases. Of these cases, 43% showed evidence of a decreased potency of carbachol by a shift in the dose-response curve to the right. The lack of agreement in efficacy and potency to increase REM sleep supports a conclusion that alterations in local muscarinic receptors are not mediating the effect of time of day. REM sleep control mechanisms down stream of the muscarinic receptors may be the responsible factors.
Asunto(s)
Carbacol/farmacología , Agonistas Colinérgicos/farmacología , Luz , Sueño REM/efectos de los fármacos , Animales , Conducta Animal/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Masculino , Estimulación Luminosa/métodos , Ratas , Ratas Long-Evans , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/efectos de la radiación , Sueño REM/efectos de la radiaciónRESUMEN
Microinjection of adenosine A1 receptor agonist or an inhibitor of adenylyl cyclase into the caudal, oral pontine reticular formation (PnOc) of the rat induces a long-lasting increase in REM sleep. Here, we report significant inhibition of forskolin-stimulated cAMP in dissected pontine tissue slices containing the PnOc incubated with the A1 receptor agonist, cyclohexaladenosine (10(-8) M). These data are consistent with adenosine A1 receptor agonist actions on REM sleep mediated through inhibition of cAMP.