ISSN:
1432-1106
Keywords:
Physostigmine
;
Atropine
;
IPSP
;
Monosynaptic reflex
;
Trigeminal
;
Motoneuron
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Physostigmine (less than 0.3 mg/kg, i. v.) was administered systemically to cats, and the effect studied on the electrical activities of trigeminal motoneurones. Physostigmine depressed the monosynaptic reflex evoked by stimulation of the mesencephalic trigeminal tract and recorded from the masseter nerve, and potentiated the inhibition of this monosynaptic reflex by volleys in skin nerves. This effect began within 1–2 min after the injection of physostigmine, reached a maximum at 5–12 min and thereafter decayed gradually. Skin nerve stimulation induced inhibitory postsynaptic potentials (IPSPs) in trigeminal motoneurones. After physostigmine administration these IPSPs were increased in amplitude, and were accompanied by a prolonged, late hyperpolarization. The early phase of this IPSP and the late hyperpolarization showed different sensitivities to the intracellular injection of chloride ions and to polarizing currents, indicating different mechanisms for their production. The effect of physostigmine was blocked by atropine (1 mg/kg, i.v.) but not by dihydro-β-erythroidine (0.5 mg/kg, i.v.).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00234283
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