Site of action of chlorpromazine and mephenesin in experimental tetanus. (1/18)

The anti-tetanus activities of chlorpromazine and mephenesin have been determined quantitatively in intact, spinal and decerebrate rabbits with local tetanus. The activity of chlorpromazine in the spinal animal differed from that in the intact and decerebrate animal and depended on the level of brain-stem section. Mephenesin was equally effective in all preparations and probably suppressed tetanus by blocking transmission in motor pathways in the spinal cord.  (+info)

THE SELECTIVITY OF DRUGS BLOCKING GANGLIONIC TRANSMISSION IN THE RAT. (2/18)

By comparing the effects on ganglionic transmission and on the pre- and post-ganglionic nerves in the isolated superior cervical ganglion preparation of the rat, the selectivity of several drugs was assessed quantitatively. Hexamethonium, tetraethylammonium, nicotine and tubocurarine blocked transmission in concentrations which did not affect nervous conduction and were considered to be highly selective in action. Atropine, amylobarbitone and paraldehyde depressed nervous conduction appreciably in ganglion-blocking doses, but not enough to account wholly for the block in transmission and they were therefore considered as being moderately selective. The ganglion blocking actions of mephenesin, procaine, methylpentynol, methylpentynol carbamate and benactyzine were nonspecific, showing general depression of neuronal activity. Ganglion block with bretylium was nonselective in its site of depression of the postganglionic neurone in concentrations which only partly depressed the preganglionic nerve.  (+info)

The flexor reflex mediated by group II afferent fibers: effects of morphine-HCl and mephenesin. (3/18)

The effects of morphine-HCl and mephenesin on the flexor reflex mediated by group II afferent fibers were investigated. The flexor reflex was recorded by means of the electromyogram (EMG) evoked in the muscle tibialis anterior by stimulation of the ipsilateral tibial nerve in urethane-alpha-chloralose anesthetized rats. Afferent volleys corresponding to the phasic EMG component of the flexor reflex with 7.6-msec latency (flexor EMG: fEMG) were also recorded using the double volley technique. The threshold of the afferent volleys mediating the fEMG was approximately twice as high as that of the most excitable afferent volleys, which were considered the spikes of group I afferent fibers, and the conduction velocity of the afferent volleys was 39.9 +/- 3.2 m/sec. Morphine-HCl (5 mg/kg, i.v.) did not change the amplitude of the fEMG, but mephenesin (40 and 80 mg/kg, i.v.) depressed it dose-dependently. These results suggest that the fEMG is a flexor reflex mediated by group II afferent fibers, which is not affected by morphine-HCl but depressed by mephenesin.  (+info)

Mephenesin as a relaxing agent in the treatment of tetanus; clinical experience in 12 cases. (4/18)

Maintenance of a patent airway in cases of tetanus is best accomplished by means of tracheotomy performed early in the course of the disease. This eliminates the possibility of upper respiratory obstruction and facilitates the elimination of irritating and obstructing secretions from the lower respiratory passages. In many cases the amount of sedation required is decidedly reduced following tracheotomy. The combination of phenobarbital and Tolserol(R) is very satisfactory in controlling the muscular rigidity and spasm in cases of moderately severe tetanus. In severe cases, response is not always satisfactory. Severe respiratory depression was observed in only one case in which phenobarbital and Tolserol(R) were used.  (+info)

Action of 5-hydroxytryptamine on isolated spinal cord of bullfrogs. (5/18)

Slow depolarizations of dorsal root nerve terminals and motoneurons, which were produced by 5-hydroxytryptamine (5-HT) applied directly to isolated bullfrog spinal cords, were recorded by the sucrose-gap method. These depolarizations were eliminated in the Ca-deficient Ringer's solution containing Mg, suggesting that these 5-HT depolarizations were not caused by a direct action of 5-HT on dorsal root nerve terminals or motoneurons but rather by actions of transmitters released from interneurons. Indeed, mephenesin, which is a selective blocker of polysynaptic transmission in the spinal cord, inhibited more markedly the 5-HT depolarization than the L-glutamate or GABA depolarization. The transmitter directly responsible for the generation of the 5-HT depolarization of dorsal root nerve terminals was not considered to be GABA as the 5-HT depolarization was not antagonized by picrotoxin. It would thus appear that 5-HT stimulates interneurons in the amphibian spinal cord and unknown transmitters released from these interneurons depolarize the dorsal root nerve terminals.  (+info)

Segmental patterns of vestibular-mediated synaptic inputs to axial and limb motoneurons in the neonatal mouse assessed by optical recording. (6/18)

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Organization of functional synaptic connections between medullary reticulospinal neurons and lumbar descending commissural interneurons in the neonatal mouse. (7/18)

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Vestibular-mediated synaptic inputs and pathways to sympathetic preganglionic neurons in the neonatal mouse. (8/18)

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