EFFECTS OF BULBOCAPNINE ON SPINAL REFLEXES OF ANESTHETIZED AND SPINAL RATS

Abstract

Since all of the so-called “major tranquilizers” have the ability to induce catatonic states in experimental animals, this characteristic pharmacological property is commonly being used as a clue to detecting new compounds in screening tests. However, not all compounds that produce the catalepsy in animals are “tranquilizers”. One remarkable example is bulbocapnine, an alkaloid isolated from Corydalis cava; it was first reported by Peters (1) that a catatonic state in mammals followed bulbocapnine treatment. Although it has been suggested that bulbocapnine catalepsy could serve as an experimental model for schizophrenia or Parkinson's disease, little is known of its effects on the neural components of the motor system.
In earlier experiments we found that bulbocapnine selectively depressed the spinal monosynaptic reflex response in the rat with little effect on the polysynaptic neuronal systems (2). These observations have subsequently been confirmed by Willis et al. (3, 4) in the cat.
The present report describes a further investigation of the actions of bulbocapnine on spinal reflex systems. The rat was employed in the present experiments so that the electrophysiological data could be accurately compared with the numerous behavioral observations in this species.