ABSTRACT
The present study demonstrates the effect of activation of spinal serotonergic receptors on heart rate, blood pressure and cardiac arrhythmia induced by coronary artery ligation in cervical spinal cord transected and bilaterally vagotomized dogs. Intrathecal injection of serotonin (5-HT) evoked a fall in blood pressure (mean decrease, 16 +/- 3) and a decrease in heart rate (mean change, 24 +/- 6) and these effects were blocked by intrathecal pretreatment with methysergide. The magnitude of ventricular ectopics evoked by coronary artery ligation was decreased by serotonin (mean decrease, 31 +/- 5%), and this effect of serotonin was blocked by methysergide pretreatment intrathecally (mean change, 7 +/- 5%). Methysergide per se, increased the magnitude of ventricular ectopics (mean increase, 24 +/- 5%). The serotonergic receptors of the spinal cord appear to have an inhibitory influence on the cardiovascular functions.
Subject(s)
Animals , Cardiovascular Physiological Phenomena , Dogs , Female , Ganglia, Spinal/cytology , Male , Neurons/physiology , Receptors, Serotonin/physiology , Serotonin/physiology , Serotonin Antagonists , Spinal Cord/cytologyABSTRACT
Several 1,3,4-oxadiazol-thiones were synthesised and characterized by their melting points elemental analysis and I.R. spectra. All the oxadiazol-thiones possessed anticonvulsant activity which was reflected by protection upto 80% against pentylenetetrazole induced seizures and 40% protection against maximal electroshock induced seizures. Substantiations at position-3 of oxadiazol-thiones have shown marked effect on MAO inhibitory activity. No definite correlation between monoamine oxidase inhibitory and anticonvulsant activity could be established. It was observed that by the substitution of one, two and three methyl groups in the phenyl ring of 2-arylamino methyl side chain anticonvulsant activity against both maximal electroshock induced convulsions and pentylenetetrazol induced convulsions decreases i.e. the order of activity was found to be unsubstituted greater than monomethyl greater than dimethyl greater than trimethyl.