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
The role of opioid and histaminergic system in morphine induced emesis was investigated in dogs. Morphine (25 micrograms, icv) consistently evoked emesis with an average latency of 195 +/- 29 sec which was fully accounted for by an action on the chemoreceptor trigger zone (CTZ) as its ablation rendered animals refractory to vomiting. Intraventricular pretreatment with opioid antagonist naloxone, histamine H1 antagonist mepyramine and H2 antagonists metiamide and cimetidine afforded protection to icv morphine emesis. The CSF histamine concentration was significantly raised 5 min after icv morphine administration. The results suggest that both endogenous opioid and histamine are involved in morphine emesis. Naloxone in high doses (1600 micrograms, icv) elicited emesis which was not blocked by CTZ ablation confirming our earlier report.
Subject(s)
Animals , Cimetidine/pharmacology , Dogs , Endorphins/antagonists & inhibitors , Histamine/physiology , Metiamide/pharmacology , Morphine/adverse effects , Naloxone/pharmacology , Pyrilamine/pharmacology , Vomiting/chemically inducedSubject(s)
Animals , Cimetidine/therapeutic use , Female , Guinea Pigs , Male , Rats , Stomach Ulcer/drug therapy , Valproic Acid/therapeutic useSubject(s)
Acetaminophen/metabolism , Child, Preschool , Humans , Infant , Kinetics , Liver Cirrhosis/metabolism , Phenacetin/metabolismABSTRACT
Hypertonic solutions of different substances were injected into the vertebral artery of dogs anesthetized with chloralose, preventing their access to the hypothalamic osmoreceptors by ligating the basilar artery and both the external carotid arteries. The hypertonic solution of sodium chloride produced graded inhibition of water diuresis and a concomitant rise in plasma antidiuretic hormone (ADH) level; hypertonic solution of glucose produced lesser effect. Hypertonic urea solution, on the other hand, did not alter the course of water diuresis. It was concluded that osmoreceptors are also present in the medulla which sense the changes in blood osmolarity and accordingly modify the ADH release.
Subject(s)
Animals , Diuresis/drug effects , Dogs , Female , Glucose Solution, Hypertonic/pharmacology , Hypertonic Solutions/pharmacology , Male , Medulla Oblongata/physiology , Saline Solution, Hypertonic/pharmacology , Sensory Receptor Cells/drug effects , Sucrose/pharmacology , Urea/pharmacology , Vasopressins/blood , Water/pharmacology , Water-Electrolyte Balance/drug effectsSubject(s)
Adult , Clinical Trials as Topic , Clonidine/administration & dosage , Female , Humans , Hypertension/drug therapy , Infusions, Parenteral , Male , Middle Aged , Random AllocationSubject(s)
Adult , Burimamide/administration & dosage , Histamine/pharmacology , Humans , Male , Paresthesia/chemically induced , Premedication , Pyrilamine/administration & dosage , Receptors, Histamine/drug effects , Receptors, Histamine H1/drug effects , Receptors, Histamine H2/drug effects , Skin/innervationSubject(s)
Adolescent , Adult , Age Factors , Aged , Cross-Sectional Studies , Drug Therapy/adverse effects , Female , Hospitalization , Humans , India , Male , Medication Errors , Middle AgedSubject(s)
Adolescent , Adult , Aged , Blood Pressure/drug effects , Clonidine/administration & dosage , Female , Humans , Hypertension/drug therapy , Infusions, Parenteral , Male , Middle Aged , Time FactorsSubject(s)
Analgesics , Animals , Female , Male , Mice , Monoamine Oxidase Inhibitors , Quinolines , RatsABSTRACT
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.