Changes of activity of cortical neurons induced by acetylcholine in adult and young rats.
Acetylcholine was applied microiontophoretically by means of multibarrel electrodes to neurons in the sensorimotor cortex of adult, 18-, 15-, 12-, and 9-day-old rats anesthetized with urethane. A total of 229 neurons was recorded; only 22 of them were in 18- and 15-day-old rats because of similarity of results with those from adult as well as 12-day-old animals. In adult rats 43 of 58 neurons recorded in infragranular layers responded to acetylcholine with a marked increase in their firing. In 12-day-old rats the incidence of excitatory responses to acetylcholine was also high: 59 of 86 cells again were localized predominantly in deep cortical layers (V and VI). A marked difference was observed in 9-day-old rats: only 15 of 63 neurons were excited by acetylcholine. A majority of cells did not respond at all--including units localized in infragranular layers. Two cells in layer V responded to acetylcholine by an inhibition. Our results indicate that there is a marked increase in cholinoceptivity of cortical neurons between postnatal days 9 and 12. This finding is in agreement with the finding that local application of acetylcholine can elicit an epileptogenic focus in 12-day but not in 9-day-old rat pups.
Strejcková
A
A
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Mares
P
P
Raevsky
V
V
D000109:Acetylcholine / Q000494:pharmacology*; D000375:Aging; D000818:Animals; D002415:Cats; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology; D008297:Male; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D011712:Pyramidal Tracts / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000502:physiology
D011950:Receptors, Cholinergic; D000109:Acetylcholine