Neuroscientist interested in researching the limbic system of the brain and its functioning. Interested in all aspects of the serotonergic systems in the body. Also interested in research on psychedelic medicine and the use of psychedelics to treat mental disorders.
We have been studying the development of hypertension in spontaneously hypertensive rats (SHR) fe... more We have been studying the development of hypertension in spontaneously hypertensive rats (SHR) fed a low protein diet. The effects of a low protein diet upon food and water intake were examined. Body weight gain, food and water intake were measured in three to twenty-three week-old SHR and Wistar Kyoto rats (WKY) fed diets containing 8%, 15% or 25% casein. Body weights of SHR and WKY fed an 8% casein diet were significantly lower at 23 weeks than rats on the higher protein diets, although both groups on the 8% diet consumed more food and water per g of body weight. In addition, SHR fed an 8% casein diet drank less water per gram of food than WKY or SHR fed 15% and 25% casein diets. These results indicate that changes in food and water intake, as a consequence of low protein diets, should be an additional consideration when examining the effects of dietary protein on the development of hypertension.
In this series of articles, several new hypotheses on sleep and dreaming are presented. In each c... more In this series of articles, several new hypotheses on sleep and dreaming are presented. In each case, we feel the data do not adequately support the hypothesis. In their lengthy discourse, Hobson et al. represent to us the familiar reciprocal interaction model dressed in new clothes, but expanded beyond reasonable testability. Vertes & Eastman have proposed that REM sleep is not involved in memory consolidation. However, we do not find their arguments persuasive in that limited differences in activity in REM and waking do not lend credence to the idea that memory consolidation occurs in one state and not the other. Solms makes an argument that dreams are generated from the dopaminergic forebrain based largely on pathological lesion studies in humans. We recognize that this argument has some intuitive appeal and agree with some of the tenets but we do not feel that the arguments are completely convincing due to the lack of anatomical controls, including symmetry and laterality. On the whole, there are interesting arguments put forward in these target articles but the evidence does not convince us that new vistas are opened. No Holy Grail of sleep here![Hobson et al.; Solms; Vertes & Eastman]
Delta-9-tetrahydrocannabinol (THC) was administered to young male Fischer-344 (CDF) and Sprague-D... more Delta-9-tetrahydrocannabinol (THC) was administered to young male Fischer-344 (CDF) and Sprague-Dawley (CD) rats on days 30-50 of age. Doses of THC consisted of 20, 10 or 5 doses of 10 mg/kg spaced over the 20-day period. On day 140 animals were exposed to a 15 sec 1.5 mA scrambled foot-shock. Latency for withdrawal from 55 degrees C water was used as a measure for analgesia. Both CDF and CD rats showed a foot-shock induced analgesia (FSIA). Animals which had received 5 or 10 doses of THC in youth showed an enhanced response to foot-shock in the CDF rat. The foot-shock was then paired with an unconditioned stimulus (shock environment) and a conditioned analgesia developed over 4 days. At weekly intervals thereafter animals were tested in the shock environment only for extinction of the analgesic response. Over 4 weeks, analgesia did not show extinction in the CDF rat. Extinction of the response was observed in the veh and 20 dose groups in the CD rat; whereas a resistance to extinction was observed in the other groups. The CDF rats were then sacrificed following the last extinction trial and serum corticosterone and prolactin measured. Five and 10 doses of THC decreased prolactin levels; stress, however, increased these levels above the levels in VEH treated animals exposed to stress. Extinction of a fixed ratio 10 as well as exposure to fixed ratio strain in the CD rat were not affected by THC. These data suggest that THC administered during postweaning development alters endogenous systems which mediate the animals response to stress.
We have been studying the development of hypertension in spontaneously hypertensive rats (SHR) fe... more We have been studying the development of hypertension in spontaneously hypertensive rats (SHR) fed a low protein diet. The effects of a low protein diet upon food and water intake were examined. Body weight gain, food and water intake were measured in three to twenty-three week-old SHR and Wistar Kyoto rats (WKY) fed diets containing 8%, 15% or 25% casein. Body weights of SHR and WKY fed an 8% casein diet were significantly lower at 23 weeks than rats on the higher protein diets, although both groups on the 8% diet consumed more food and water per g of body weight. In addition, SHR fed an 8% casein diet drank less water per gram of food than WKY or SHR fed 15% and 25% casein diets. These results indicate that changes in food and water intake, as a consequence of low protein diets, should be an additional consideration when examining the effects of dietary protein on the development of hypertension.
In this series of articles, several new hypotheses on sleep and dreaming are presented. In each c... more In this series of articles, several new hypotheses on sleep and dreaming are presented. In each case, we feel the data do not adequately support the hypothesis. In their lengthy discourse, Hobson et al. represent to us the familiar reciprocal interaction model dressed in new clothes, but expanded beyond reasonable testability. Vertes & Eastman have proposed that REM sleep is not involved in memory consolidation. However, we do not find their arguments persuasive in that limited differences in activity in REM and waking do not lend credence to the idea that memory consolidation occurs in one state and not the other. Solms makes an argument that dreams are generated from the dopaminergic forebrain based largely on pathological lesion studies in humans. We recognize that this argument has some intuitive appeal and agree with some of the tenets but we do not feel that the arguments are completely convincing due to the lack of anatomical controls, including symmetry and laterality. On the whole, there are interesting arguments put forward in these target articles but the evidence does not convince us that new vistas are opened. No Holy Grail of sleep here![Hobson et al.; Solms; Vertes & Eastman]
Delta-9-tetrahydrocannabinol (THC) was administered to young male Fischer-344 (CDF) and Sprague-D... more Delta-9-tetrahydrocannabinol (THC) was administered to young male Fischer-344 (CDF) and Sprague-Dawley (CD) rats on days 30-50 of age. Doses of THC consisted of 20, 10 or 5 doses of 10 mg/kg spaced over the 20-day period. On day 140 animals were exposed to a 15 sec 1.5 mA scrambled foot-shock. Latency for withdrawal from 55 degrees C water was used as a measure for analgesia. Both CDF and CD rats showed a foot-shock induced analgesia (FSIA). Animals which had received 5 or 10 doses of THC in youth showed an enhanced response to foot-shock in the CDF rat. The foot-shock was then paired with an unconditioned stimulus (shock environment) and a conditioned analgesia developed over 4 days. At weekly intervals thereafter animals were tested in the shock environment only for extinction of the analgesic response. Over 4 weeks, analgesia did not show extinction in the CDF rat. Extinction of the response was observed in the veh and 20 dose groups in the CD rat; whereas a resistance to extinction was observed in the other groups. The CDF rats were then sacrificed following the last extinction trial and serum corticosterone and prolactin measured. Five and 10 doses of THC decreased prolactin levels; stress, however, increased these levels above the levels in VEH treated animals exposed to stress. Extinction of a fixed ratio 10 as well as exposure to fixed ratio strain in the CD rat were not affected by THC. These data suggest that THC administered during postweaning development alters endogenous systems which mediate the animals response to stress.
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Papers by David Mokler