EFFECTS OF HONEY CONTAINING GRAYANOTOXIN-I ON FROG GASTROCNEMIUS-MUSCLE

The presence of grayanotoxins (GTX-I , GTX-II and GTX-III) in honey samples from the Mediterranean Sea and Black Sea regions of Turkey and the effect of honey containing GTX-I on the threshold stimulus voltage of frog gastrocnemius muscle were studied. We used 2 groups of gastrocnemius muscles isolated from curarized or noncurarized frogs. The threshold voltage was measured by external perfusion with a polygraphic system. Isolated muscle preparations were perfused separately with Clark-frog-Ringer's solution containing honey solutions from the Mediterranean Sea region (normal) or with honey solutions from the Black Sea region (GTX-I-containing, poisonous). There was no significant difference between the normal and poisonous honey groups data with the curarized preparations. But in the noncurarized preparations, the honey containing GTX-I significantly decreased the threshold voltage in comparison with normal honey. These findings suggest the effect of GTX-I on frog neuromuscular junctions is due to an increase in membrane permeability to sodium ions

Effect of grayanotoxin II on in vitro mitotic activity of human lymphocytes

Extracts of Rhododendron species and honey obtained from such species, which are used in folk medicines in Japan and Turkey, contain grayanotoxins. The effects of one of these toxins, grayanotoxin II, on the mitotic activity of cultured human lymphocytes were investigated. The mitotic index of the lymphocytes was increased by concentrations of 10(-4) and 10(-3) M grayanotoxin II, significantly so in the case of the higher concentration; the increase appeared to be proportional to the concentration of the toxin

Maternal l-thyroxine treatment during lactation affects learning and anxiety-like behaviors but not spatial memory in adult rat progeny

Background The present study compared behavioral and molecular indicators of hippocampal function in l-thyroxine treated rats to determine whether thyroid hormone excessiveness produces relatively stable lifelong changes. Methods Hyperthyroidism was induced in rats by daily injections of l-thyroxine (0.2 mg/kg) to their dams for lactation period (MOH: maternal-onset hyperthyroidism) or to the rats itself during the young adult period (AOH: adult-onset hyperthyroidism; between the day 39-60). Spatial learning was assessed in the Morris Water Maze (MWM). Levels of type 2 and type 3 deiodinases, Erk1/2, JNK and P38(MAPK) were assessed via western blotting in the hippocampus of trained rats. Measurements were all done in rats aged 60-66 days. Results In MWM, maternally treated rats with l-thyroxine swam more away from the hidden platform, with showing more anxiety-like behavior, as compared to the rats treated or no treated with l-thyroxine in young adulthood. In spite of impaired acquisition, MOH group was not significantly different from the other groups in probe trial. In Western blot of the hippocampus, a decreased the expression of P38MAPK was found in rats treated with l-thyroxine in young adulthood period. However, maternal treatment with l-thyroxine resulted in an increased expression of Type 2 deiodinase and a tendency toward decreased expression of total and phosphorylated ERK1/2. No detectable band for type 3 deiodinase, p-JNK and p-P38(MAPK) was observed in all three groups. Conclusion These results suggest that perinatal excessiveness of thyroid hormone has longstanding effects on hippocampal function and may account for memory problems experienced by adolescents with lactational hyperthyroidism

P50 variations in Behcet's patients without neurologic findings

Arslan, Mustafa/0000-0003-4882-5063; Suer, Cem/0000-0002-6455-6644WOS: 000244533700010PubMed: 21857619Objective: In the present study, subclinical lesion involvement was investigated using the P50 component in Behcet's patients without neurological manifestation. Methods: We performed this clinical research in Erciyes University, Faculty of Medicine between December 2000 and November 2001. The studies were carried out on 18 Behcet's patients without neurologic findings and 18 volunteers for control. Standard Ag/AgCl electrodes in plastic cups were used for monopolar EEG derivations. They were attached with electrode paste and tape at the Cz (vertex) according to the 10-20 system. The auditory stimuli were delivered in pairs. The P50 waves, which may be taken from approximately 50 msec from the stimuli, were collected by computer system. Amplitudes and latencies of the P50 components were measured in the same system. Results: This study showed that the suppression of P50 responses performed by the test stimuli, was significantly more decreased in Behcet's patients than the control subjects. Conclusion: The decrease of the suppression of the auditory P50 response to repeated stimuli reflects a deficit in the central nervous system's ability, such as attention, cognition, and sensory input in Behcet's patients and can be used as a neurophysiological marker in subclinical lesions in these patients

Habituation of the auditory evoked potential in a short interstimulus interval paradigm

The present experiment was carried out to investigate elicitation and habituation of the auditory event related potentials with stimulus trains utilizing a short interstimulus intervals (ISI) of 1500 ms. Scalp event related potentials elicited by auditory stimuli were recorded in 10 male subjects. Thirty auditory stimuli were presented binaurally over headphones to every subject with a duration of 1000 ms, each with a constant ISI of 1500 ms. No task relevance was given to the stimuli. Wave-forms were collected using a Pentium 100 computer

Effects of cigarette smoking on cognitive processing

Several previous studies have reported that cigarette smoking enhances performance of cognitive processing. These enhancements are generally attributed to the pharmacological effects of nicotine, while there is some debate whether the effects of smoking/nicotine are a result of recovery from abstinence. Evoked potentials (EPs) and event related potentials (ERPs) of the brain have been applied as an index of information processing in a wide variety of normal and cognitive impaired subjects. This study, was carried out on 20 health students (23 +/- 2.3 years old) from the medical faculty of 007 University. Study population. comprised ten chronic cigarette smokers consuming an average of 14 +/- 4.2 cigarettes per day, with a history of smoking for more than one year. Ten non-smokers served as control. Standard oddball paradigm was presented, and EEG activity was recorded at the F-z, C-z, P-z electrode sites. Twenty responses to target stimuli were averaged at each location. N1, P2, N2, and P300 components were evaluated in these recordings. Amplitudes were measured relative to prestimulus baseline, and peak latencies were defined as the time point of maximum amplitude. It was found that there were no significant differences between either N1, P2, N2, P300 amplitudes or peak latency values of cigarette smokers and non smokers. As a result, chronic cigarette smoking generally does not improve cognitive processing

P50 variations in Behcet's patients without neurologic findings

Objective: In the present study, subclinical lesion involvement was investigated using the P50 component in Behcet's patients without neurological manifestation

Evaluation of auditory evoked potentials from the inferior colliculus in rat

This study aimed to investigate the usefulness of auditory evoked potentials (AEPs) in rats. To this end, N1, P2 latencies, and the N1-P2 amplitude of responses to different acoustic stimuli from rats, which were implanted with permanent electrodes in the inferior colliculus (IC), were evaluated and used to demonstrate the frequency characteristic's of IC region. permanent electrodes were implanted in IC regions of 7 male albino rats by the stereotaxic method. The animals were exposed to five tones series of stimuli (1000 Hz, 2000 Hz, 4000 Hz, 6000 H:, and 8000 Hz tones with 1500 ms interstimulus intervals) of 70 dB with a duration of 1000 ms. AEPs) were recorded and analyzed with the Brain-Data Acquisition system. There were no statistically significant differences in N1, P2 latencies, and the N1-P2 amplitude of AEPs from IC regions of rats as a result of changes in the frequency of stimulus. It was determined that the dominant frequency activity of the IC to acoustic stimulus was theta-alpha hand, with theta as the peak frequency. As a result it was concluded that there are similarities between the N1, P2 components of rat AEPs, and human AEPs. We have suggested that the rats may provide a useful model for investigating tire generation of middle latency components of AEP, in humans

Sex-related differences in time estimation and the role of expectancy

In this study, using auditory sequences, the authors designed on examination with three phases of stimulus-driven attention that is based on the possibility that involuntarily time shafts of attention tire caused by nonunique stimulus properties. The purpose was to investigate whether attending and temporal expectancies tire influenced by stimulus's properties and by sex. In each phase, an auditory stimulus train was presented, and the participant was asked to tap rhythmically in order to anticipate every fifth stimulus (or, in the third phase, the lack of it). The time between button pressing and stimulus onset was measured using a computer. Time estimating was accepted as a false response if the subject responded before 150 ins or 150 ms later from onset stimulus time. Error numbers were greater in Phase 3 and there was no significant difference between the male and female subjects for any of the phases when error numbers were compared. On the other hand, males pressed the button more accurately than females. lime estimation performance was affected by sex and expectancy-related motor responses are very important for time estimation