ABSTRACT
Alcoholic extracts of 48 identified species of marine flora were screened for a wide range of biological activities. Of these, 3 extracts showed diuretic activity while 2 extracts showed hypotensive effect.
Subject(s)
Eukaryota/chemistry , Animals , Antibiotics, Antineoplastic/pharmacology , Antihypertensive Agents/pharmacology , Biological Factors , Cats , Diuretics/pharmacology , Dose-Response Relationship, Drug , Guinea Pigs , Humans , India , Marine Biology , Oceans and Seas , Plant Extracts/pharmacology , Plants, Medicinal , RatsABSTRACT
Analgesia induced by pretectal stimulation in rat was analysed using suitable antagonists. Mild electrical stimulation of sites in the pretectal nucleus (PTN) caused analgesia of long duration, without signs of aversion and unassociated with motor deficit. Pretreatment of animals with ip atropine sulphate (1 mg/kg), phenoxybenzamine (5 mg/kg), sotalol (2 mg/kg) and haloperidol (1 mg/kg) but not with saline, markedly reduced the antinociceptive response to PTN stimulation. Mild PTN stimulation thus seems to induce potent and long lasting analgesia in rats probably involving multisynaptic antinociceptive pathway(s).
Subject(s)
Analgesia/methods , Animals , Atropine/pharmacology , Electric Stimulation/instrumentation , Haloperidol/pharmacology , Male , Neurotransmitter Agents/antagonists & inhibitors , Phenoxybenzamine/pharmacology , Rats , Sotalol/pharmacology , Tail/physiology , Tectum Mesencephali/drug effectsABSTRACT
Mild and brief electrical stimulation of sites in the pretectal nucleus of rat produced analgesia (SPA) of long duration without significant aversion. Intracerebroventricular (icv) administration of 5-HT receptor antagonists methysergide (50 micrograms) and ketanserin (50 micrograms) and the dopaminergic antagonist haloperidol (50 micrograms) had no significant effect on pretectal SPA, but alpha and beta adrenoceptor antagonists phenoxybenzamine (50 micrograms) and sotalol (50 micrograms) on icv injection significantly antagonised the pretectal SPA. The results suggest that pretectal SPA involves activation of central adrenoceptors.
Subject(s)
Analgesia , Animals , Biogenic Monoamines/antagonists & inhibitors , Electric Stimulation , Haloperidol/pharmacology , Ketanserin/pharmacology , Methysergide/pharmacology , Phenoxybenzamine/pharmacology , Rats , Serotonin Antagonists , Sotalol/pharmacologyABSTRACT
Opioid activity of a homologous series of met-enkephalin alkylamides was analysed. In guinea pig ileum test, the hexylamide derivative was most active, whereas the isopropylamide derivative was most potent in analgesia test. The results suggest that structural changes of this type at the C-terminus of the pentapeptide improve the opioid activity.
Subject(s)
Amides , Animals , Chemical Phenomena , Chemistry , Enkephalin, Methionine/pharmacology , Guinea Pigs , Ileum/drug effects , Morphine/pharmacologyABSTRACT
Six enkephalin analogues (N-substituted amides and imides of [D-Ala2, Met5]-enkephalin) were synthesized and tested for opioid activity. All the compounds, except one i.e., compound IV, showed analgesic activity which was much higher than Met-enkephalin and morphine in mice and inhibited electrically induced contractions of isolated guineapig ileum, [D-Ala2, Met5]-enkephalin-morpholide and [D-Ala2, Met5]-enkephalin-beta-Ala-amide were the most potent analgesics and nearly 6 and 500 times as active as morphine and Met-enkephalin respectively. Both the compounds were equipotent on the guineapig ileum preparation, whereas the beta-Ala-amide was about twice as active as the morpholide in the electrically stimulated mouse vas deferens preparation.