dihydroergotoxine and raubasine

Topics: Arterial Occlusive Diseases; Cardiovascular Agents; Cinnarizine; Clinical Trials as Topic; Dihydroergotamine; Dihydroergotoxine; Drug Combinations; Exercise Test; Flunarizine; Humans; Intermittent Claudication; Nafronyl; Pentoxifylline; Placebos; Pyrrolidines; Secologanin Tryptamine Alkaloids; Yohimbine

Amnesia can be induced in rats in the passive avoidance paradigm by administration of scopolamine, a central muscarinic receptor antagonist. Tacrine or galanthamine, inhibitors of acetylcholinesterase, given in conjunction with scopolamine partially reversed the scopolamine-induced deficit in passive avoidance performance. Four so-called cognitive enhancers, all widely used for the treatment of the symptoms associated with mental aging, cerebral insufficiency and senile memory disorder, were investigated in this paradigm. Piracetam, an extract of Ginkgo biloba, dihydroergocristine and a combination of raubasine with dihydroergocristine, all attenuated the amnesia induced by scopolamine. In contrast, nicergoline had no significant effect. Raubasine alone also failed to significantly attenuate scopolamine-induced amnesia, although some doses of raubasine had a non-significant tendency (P less than 0.10) to reduce the amnesia.

Topics: Amnesia; Animals; Avoidance Learning; Cognition; Dihydroergotoxine; Dose-Response Relationship, Drug; Galantamine; Ginkgo biloba; Male; Nicergoline; Piracetam; Plant Extracts; Rats; Rats, Inbred Strains; Scopolamine; Secologanin Tryptamine Alkaloids; Tacrine; Yohimbine

Topics: Acetylcholine; Aging; Animals; Avoidance Learning; Cerebrovascular Circulation; Dihydroergotoxine; Male; Rats; Receptors, Serotonin; Secologanin Tryptamine Alkaloids; Yohimbine

Aspirin is known to be ototoxic when administered at high doses. Its mode of action is unknown but an alteration of the vascular function has been suspected. To further document this hypothesis, acute effects of some vasoactive agents on the ototoxicity of aspirin were tested in experiments on the guinea pig using sensori-neural electrophysiological responses and morphometry of the vessels of the stria and the spiral lamina. Electrophysiological measures showed no modification of sensory responses but neural responses revealed clear changes after administration of noradrenalin related agents, limited modifications after a drug acting partly as a serotonin antagonist, and no change after a dopaminergic agent. Morphometric studies showed no modification of the strial but some effect on the spiral vessels. The results are compatible with the hypothesis of a vascular involvement in the ototoxicity of aspirin and they point toward an interaction with the noradrenergic sympathetic cochlear system in the spiral lamina.

Topics: Animals; Aspirin; Auditory Threshold; Cochlea; Cochlear Microphonic Potentials; Dihydroergotoxine; Guinea Pigs; Metaraminol; Nafronyl; Piribedil; Secologanin Tryptamine Alkaloids; Spiral Lamina; Stria Vascularis; Vasodilator Agents; Yohimbine

In strips of isolated canine basilar arteries, previously labeled with 3 X 10(-7) M of either [3H]noradrenaline or [3H]serotonin, three consecutive periods of electrical stimulation (2 Hz) evoked a reproducible overflow of the respective [3H]amine. Increasing concentrations of raubasine (7.5 X 10(-7)-7.5 X 10(-6) M) did not influence the spontaneous 3H efflux but increased the stimulation-induced 3H overflow in a concentration-dependent way. The highest concentration of raubasine used (2.5 X 10(-5) M) caused an increased spontaneous 3H efflux but no longer augmented the stimulation-induced 3H overflow. Dihydroergocristine (5.4 X 10(-8)-1.8 X 10(-6) M) did not affect the spontaneous 3H efflux; the compound slightly but significantly reduced the stimulation-evoked 3H overflow concentration dependently. High concentrations of Iskedyl (mixtures of raubasine and dihydroergocristine in a 14:1 molar ratio) augmented the spontaneous 3H efflux and moderately decreased the stimulation-induced 3H overflow. Although some quantitative differences were noted, the compounds exerted similar effects on arteries labeled with either [3H]noradrenaline or [3H]serotonin. The most important difference detected was that DHEC decreased the stimulation-induced release of [3H]serotonin more than that of [3H]noradrenaline. Our results allow a comparison of [3H]noradrenaline and [3H]serotonin release in the dog basilar artery: the basal fractional release of [3H]serotonin was higher than that of [3H]noradrenaline while the stimulation-induced overflow was equal in both groups of tissues. The constituents of Iskedyl can profoundly affect the release of the neurotransmitters. Raubasine, a presynaptic alpha-receptor antagonist, increases the stimulation-induced release of the neurotransmitters and both DHEC, a presynaptic receptor agonist, and the combination of the compounds, Iskedyl, decrease the release of the neurotransmitters.

Topics: Animals; Basilar Artery; Dihydroergotoxine; Dogs; Drug Combinations; Electric Stimulation; In Vitro Techniques; Norepinephrine; Secologanin Tryptamine Alkaloids; Serotonin; Yohimbine

Concrete cross-sectional studies of the organic brain syndrome, carried out periodically, attempt to establish for the parameters evaluation of substrate damage--and different noopsychopathological rating-scales for the measurement of brain capacity impairment. Beyond the level of the purely correlative-statistical point of view of the relationship between parameter and score changes, demanding for a quantitative model which could provide not only a description, but also an explanation for such a relationship. The fact that there can only be a question here of a "quantitative causality" embracing non-specificity of toxic substances and relative to acute and chronic diffuse organic brain syndromes. It results, that quantitative causality meets the requirements of an exponential function model and that one can validate such models through correlative-statistical methods. This has already been carried out by Ball and Taylor.

Topics: Adult; Aged; Cerebrovascular Disorders; Dihydroergotamine; Dihydroergotoxine; Drug Combinations; Humans; Middle Aged; Neurocognitive Disorders; Psychological Tests; Secologanin Tryptamine Alkaloids; Self-Assessment; Yohimbine

Topics: Adrenergic alpha-Antagonists; Animals; Dihydroergotoxine; Drug Combinations; Hemodynamics; Male; Medulla Oblongata; Rats; Rats, Inbred Strains; Secologanin Tryptamine Alkaloids; Yohimbine

Topics: Animals; Bile; Dihydroergotamine; Dihydroergotoxine; Dogs; Drug Combinations; Humans; Isomerism; Kinetics; Protein Binding; Secologanin Tryptamine Alkaloids; Tissue Distribution; Yohimbine