Pontine microinjection of carbachol and critical zone for inducing postural atonia in reflexively standing decerebrate cats.
Pontine carbachol injection sites critically related to the induction of postural atonia were explored in reflexively standing acute decerebrate cats. Carbachol (4.0 micrograms/0.25 microliter) and atropine (2.0 micrograms/0.25 microliter) were focally injected into the pontomedullary reticular formation, and their effects on hindlimb extensor muscle tone were studied. The effective carbachol injection sites were concentrated in the region between P 1.5 and P 3.5, H -3.0 and H -5.0, and LR 1.2 and LR 2.5 (Horsley-Clarke coordinates). The effective sites corresponded to the dorsomedial part of both the nucleus reticularis pontis oralis (NRPo) and the rostral portion of the nucleus reticularis pontis caudalis (NRPc). The mean latency to the beginning of carbachol-induced postural atonia was about 90 s (92 +/- 28 s; n = 24).
Takakusaki
K
K
Department of Physiology II, Asahikawa Medical College, Japan.
Matsuyama
K
K
Kobayashi
Y
Y
Kohyama
J
J
Mori
S
S
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000008:administration & dosage / Q000494:pharmacology*; D002415:Cats; D003655:Decerebrate State / Q000503:physiopathology*; D004594:Electrophysiology; D005260:Female; D008297:Male; D008845:Microinjections; D009129:Muscle Tonus / Q000187:drug effects; D011149:Pons / Q000033:anatomy & histology; D011187:Posture / Q000502:physiology*; D012018:Reflex / Q000187:drug effects*; D012154:Reticular Formation / Q000187:drug effects
D001285:Atropine; D002217:Carbachol