Microinjection of carbachol into the pontine area is unable to modify insomnia induced by p-cholorophenylalanine (PCPA).
It has previously been shown that cholinergic drugs administered into the pontine area (field tegmental gigantocellular, FTG) are capable of inducing significant increases of rapid eye movement (REM) sleep periods in normal cats. The purpose of this study was to determine whether such cholinergic stimulation is capable of inducing similar effects in p-chlorophenylalanine (PCPA) insomniac cats. Four groups (n = 6) of cats were used in this study. The first two groups received a microinjection of either, saline (1 microliter) or carbachol (8 micrograms/1 microliter). The last two groups, prior to the microinjection, received PCPA (400 mg/kg) pre-treatment. Histological analysis showed that the tips of the cannulae were located in the caudal FTG, at the level of the ponto-medullary union. Results showed that carbachol significantly increased REM sleep in normal cats as compared to saline, whereas, carbachol was unable to modify the insomnia induced by PCPA. These findings suggest that cholinergic effects on REM sleep require a serotoninergic system. The results are discussed in terms of acetylcholine/serotonin interaction in the control of REM sleep.
Drucker-Colín
R
R
Departamento de Neurociencias, Universidad Nacional Autónoma de México, D.F.
Prospéro-García
O
O
D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002415:Cats; D002799:Cholinergic Fibers / Q000187:drug effects / Q000502:physiology*; D005260:Female; D010134:Fenclonine; D008297:Male; D008845:Microinjections; D011149:Pons / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D012701:Serotonin / Q000502:physiology; D007319:Sleep Initiation and Maintenance Disorders / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D012895:Sleep, REM / Q000187:drug effects
D012701:Serotonin; D002217:Carbachol; D010134:Fenclonine