strychnine and Anxiety-Disorders

Pentylenetetrazol (PTZ), a GABA(A) receptor antagonist and prototypical anxiogenic drug, has been extensively utilized in animal models of anxiety. PTZ produces a reliable discriminative stimulus which is largely mediated by the GABA(A) receptor. Several classes of compounds can modulate the PTZ discriminative stimulus including 5-HT(1A), 5-HT(3), NMDA, glycine, and L-type calcium channel ligands. Spontaneous PTZ-lever responding is seen in trained rats during withdrawal from GABA(A) receptor compounds such as chlordiazepoxide and diazepam, and also ethanol, morphine, nicotine, cocaine, haloperidol, and phencyclidine. This effect is largely mediated by the GABA(A) receptor, which suggests that anxiety may be part of a generalized withdrawal syndrome mediated by the GABA(A) receptor. There are also important hormonal influences on PTZ. Corticosterone plays some role in mediation of its anxiogenic effects. There is a marked sex difference in response to the discriminative stimulus effects of PTZ, and estrogens appear to protect against its anxiogenic effects. Further work with the PTZ drug discrimination is warranted for characterization of anxiety during withdrawal, and the hormonal mechanisms of anxiety.

Topics: Animals; Anxiety Disorders; Calcium Channels, L-Type; Discrimination, Psychological; Drug Interactions; GABA Antagonists; GABA-A Receptor Antagonists; Glycine Agents; Models, Animal; Nicotine; Pentylenetetrazole; Pituitary-Adrenal System; Receptors, GABA-A; Receptors, Glycine; Receptors, Nicotinic; Receptors, Serotonin; Serotonin; Sex Factors; Strychnine; Substance Withdrawal Syndrome

Ignatia amara (Ignatia), a remedy made from the Strychnos ignatii seeds, is used for anxiety-related symptoms, but consistent evidence of its activity in reproducible experimental models is lacking. An investigation was performed in order to assess on mice, by means of emotional response models, the activity of homeopathic Ignatia dilutions/dynamizations.. Groups of 8 mice of the CD1 albino strain were treated intraperitoneally for 9 days with 0.3ml of five centesimal (C) dilutions/dynamizations of Ignatia (4C, 5C, 7C, 9C and 30C). Control mice were treated with the same hydroalcoholic (0.3%) solution used to dilute the medicines. Diazepam (1mg/kg) was the positive reference drug. Validated test models for locomotion and emotional response, the Open-Field (OF) and the Light-Dark (LD) tests, were employed. Five replications of the same protocol were carried out, in a randomised way using coded drugs/controls.. In the OF the general locomotion of mice was slightly decreased by Ignatia 4C, but not by Ignatia 5C, 7C, 9C and 30C, indicating the absence of unspecific motor impairment or sedation by these dilutions/dynamizations. Ignatia and diazepam seemed to decrease the number of urine spots released in the OF during 10min, with borderline significance (P=0.083). In the LD the tested medicine showed anxiolytic-like activity (increase of time spent and distance travelled in the lit area), though to a lesser extent than diazepam. The highest and most significant difference with untreated controls (P<0.01) was observed with the 9C dilution/dynamization. Among the 5 replication experiments, the best drug effects were obtained where the baseline anxiety of mice was higher.. Homeopathic Ignatia dilutions/dynamizations (peak at 9C) modify some emotion-related symptoms in laboratory mice without affecting locomotion.

Topics: Animals; Anti-Anxiety Agents; Anxiety Disorders; Disease Models, Animal; Exploratory Behavior; Homeopathy; Male; Mice; Mice, Inbred Strains; Phytotherapy; Plant Extracts; Seeds; Strychnos