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There is recent evidence that deprenyl may have anticonvulsant action in a rat kindling model of epilepsy as well as in a maximal electroshock model. We therefore investigated the effect of deprenyl on the brain sensitivity threshold to pentylenetetrazol (PTZ)-induced maximal seizures in Lewis rats, in a model that provides pharmacodynamic information free of pharmacokinetic interference. The novel finding of this investigation was the anticonvulsant effect of deprenyl following repetitive administration whereas a single deprenyl dose did not affect the PTZ concentrations required to induce maximal seizures. The data suggests that the mechanism of this effect is not associated with the dopaminergic activity of deprenyl since pretreatment with both bromocriptine (a dopamine D2 agonist) and haloperidol (dopamine antagonist) did not affect the seizure threshold, whereas levodopa caused a proconvulsant effect. It was also concluded that the mechanism is not related to changes in acetylcholine levels since prolonged pretreatment with deprenyl did not attenuate the brain sensitivity to pilocarpine-induced seizures. The fact that long term administration of deprenyl was needed to produce its anticonvulsant effect may indicate that the anticonvulsant effect of deprenyl may be due to changes in levels of certain endogenous compounds or down or up-regulation of relevant receptor/effector units.

The purpose of the present investigation was to evaluate whether antiinflammatory drugs affect the pharmacodynamics of theophylline-induced seizures. Adult male Lewis rats were treated with either dexamethasone (DEX), hydrocortisone (HYD), ibuprofen (IBU), or mefenamic acid (MFA), for 4 consecutive days. On the fourth day they received a constant infusion of theophylline (2 mg/min IV) until the onset of maximal seizures. Then, blood and cerebrospinal fluid (CSF) were obtained for theophylline concentration determinations by HPLC. It was found that pretreatment with the corticosteroids DEX and HYD elevated the CSF theophylline concentration required to induce maximal seizures in comparison to the untreated rats (242 +/- 6, 232 +/- 6, and 203 +/- 10 mg/l, respectively, n = 10, p0.05). MFA also increased the CSF theophylline concentration at that end-point in comparison to the controls (p0.01), whereas pretreatment with IBU had no effect (280 +/- 10 MFA, 225 +/- 9 IBU vs. 220 +/- 8 controls, n = 12). The data suggests that concomitant treatment with antiinflammatory drugs, together with theophylline, do not increase the risk for theophylline-induced seizures. Moreover, in certain cases they may elevate the seizure threshold and protect against these hazardous episodes.

We studied heart rate variability in rats by power scaling spectral analysis (PSSA), autoregressive modeling (AR), and detrended fluctuation analysis (DFA), assessed stability by coefficient of variation between consecutive 6-h epochs, and then compared cross-correlation among techniques. These same parameters were checked from baseline conditions through acute and chronic disease states (streptozotocin-induced diabetes) followed by therapeutic intervention (insulin). Cross-correlation between methods over the entire time period was r = 0.94 (DFA and PSSA), r = 0.81 (DFA and AR), and r = 0.77 (AR and PSSA). Under baseline conditions the scaling parameter measured by DFA and PSSA and the high-frequency (HF) component measured by AR fluctuated around an average value, but these fluctuations were different for the three methods. After diabetes induction, a strong correlation was found between the HF power and the short-term scaling parameter. Despite their differences in methodology, DFA and PSSA assess changes in parasympathetic tone as detected by autoregressive modeling.

Asymmetrical shoulder, thoracic and buttock pressure affect ipsilateral nasal resistance, autonomic tone, and hemisphericity. This factor must be taken into consideration when conducting psychological experimentation, and, in fact, may have confounded much prior research.

Research on second language acquisition has recently focused on the concept of brain hemisphericity. Since the nasal cycle indexes brain hemisphericity and a deviated nasal septum itself affected by structural brain dominance may prevent nasal cycling, we investigated the presence of septa! deviation and inferior turbinate hypertrophy in 11 expert translators. We found that 10 of the 11 subjects demonstrated both a straight nasal septum and right unilateral inferior turbinate hypertrophy, an extremely rare anatomical phenomenon. The one-tailed binomial test was extremely significant (p

Sir .—Silber and D'Angelo1 reported psychosis and seizures following the injection of penicillin G procaine in adolescents. This syndrome, known as Hoigne's syndrome, is an acute, toxic, nonallergic reaction to the intramuscular administration of aqueous penicillin G procaine. The reaction is to the procaine and not to the penicillin component. I would like to suggest four possible explanations for this phenomenon: (1) the increased male-to-female ratio and anomalous drug actions, (2) the increased male-to-female ratio and essential fatty acid deficiency, (3) the effects of penicillin on prostaglandin biosynthesis, and (4) the effects of procaine on prostaglandin biosynthesis. Hoigne's syndrome is six times more common in males than in females. 2 Anomalous dominance is much more common in males, anomalous drug actions are probably much higher in persons with anomalous dominance, and it is possible that acetylator drug metabolism is related to anomalous dominance patterns. 3 It is especially interesting to