Prolame produces anxiolytic- and antidepressant-like effects in middle-aged female rats with less uterotrophic effects than 17ß-estradiol.

Estrogen hormone replacement therapy (EHRT), improving women's life quality at menopause, reduces anxiety and depression symptoms associated with ovarian hormonal decline. However, its potential adverse effects, like thromboembolism and cancer risk, limit its use. Prolame is a synthetic 17ß-amino estrogen with antithrombotic actions that exerts anxiolytic- and antidepressant-like effects on young adult ovariectomized female rats. It is unknown if prolame's effects may be observed in age and endocrine conditions emulating menopause. This study aimed to identify the antidepressant- and anxiolytic-like effects of prolame and E2 (used as a reference estrogen treatment) in middle-aged female rats coursing with irregular cycles, in two different conditions: ovariectomized or gonadally intact. Results were compared with those from young adult ovariectomized rats. Prolame (60 or 120 µg/kg), 17ß-estradiol (E2, 40 or 80 µg/kg), or vehicle were chronically administered, and their effects were evaluated in the elevated plus-maze, defensive burying behavior test, open field test, and forced swimming test. Uterotrophic actions were estimated by uterine weight related to body weight. Prolame and E2 produced robust anxiolytic- and antidepressant-like effects in young adult ovariectomized rats, but these effects were absent in gonadally intact middle-aged rats. Interestingly, only prolame induced anxiolytic- and antidepressant-like effects in middle-aged ovariectomized rats. Uterotrophic effects of prolame were weaker than E2 effects, notably in middle-aged females. Altogether, present data support the notion that prolame has the potential to be considered an EHRT with relevant psychoactive actions and with apparently lower adverse-side effects, especially in middle-aged populations.

Dehydroepiandrosterone increases the number and dendrite maturation of doublecortin cells in the dentate gyrus of middle age male Wistar rats exposed to chronic mild stress.

Aging increases the vulnerability to stress and risk of developing depression. These changes have been related to a reduction of dehydroepiandrosterone (DHEA) levels, an adrenal steroid with anti-stress effects. Also, adult hippocampal neurogenesis decreases during aging and its alteration or impaired is related to the development of depression. Besides, it has been hypothesized that DHEA increases the formation of new neurons. However, it is unknown whether treatment with DHEA in aging may stimulate the dendrite maturation of newborn neurons and reversing depressive-like signs evoked by chronic stress exposure. Here aged male rats (14 months old) were subjected to a scheme of chronic mild stress (CMS) during six weeks, received a treatment with DHEA from the third week of CMS. Changes in body weight and sucrose preference (SP) were measured once a week. DHEA levels were measured in serum, identification of doublecortin-(DCX)-, BrdU- and BrdU/NeuN-labeled cells was done in the dentate gyrus of the hippocampus. CMS produced a gradual reduction in the body weight, but no changes in the SP were observed. Treatment enhanced levels of DHEA, but lack of recovery on body weight of stressed rats. Aging reduced the number of DCX-, BrdU- and BrdU/NeuN- cells but DHEA just significantly increased the number of DCX-cells in rats under CMS and controls, reaching levels of young non-stressed rats (used here as a reference of an optimal status of health). In rats under CMS, DHEA facilitated dendritic maturation of immature new neurons. Our results reveal that DHEA improves neural plasticity even in conditions of CMS in middle age rats. Thus, this hormone reverted the decrement of DCX-cells caused during normal aging.

Prosexual Effect of Chrysactinia mexicana A. Gray (Asteraceae), False Damiana, in a Model of Male Sexual Behavior.

Chrysactinia mexicana A. Gray (Asteraceae) and Turnera diffusa Willd (Turneraceae) are employed in traditional medicine as aphrodisiacs; however, there is no scientific evidence supporting the prosexual properties of C. mexicana. The aim of this study was to determine whether an aqueous extract of C. mexicana (Cm) stimulates rat male sexual behavior in the sexual exhaustion paradigm. Sexually exhausted (SExh) male rats were treated with Cm (80, 160, and 320 mg/kg), an aqueous extract of T. diffusa (Td), or yohimbine. The sexual exhaustion state in the control group was characterized by a low percentage of males exhibiting mounts, intromissions, and ejaculations and no males demonstrating mating behavior after ejaculation. Cm (320 mg/kg), Td, or yohimbine significantly increased the proportion of SExh rats that ejaculated and resumed copulation after ejaculation. In males that exhibited reversal of sexual exhaustion, Cm (320 mg/kg) improved sexual performance by reducing the number of intromissions and shrinking ejaculation latency. The effects of treatments on sexual behavior were not related with alterations in general locomotion. In conclusion, the prosexual effects of Cm, as well as those of Td, are established at a central level, which supports the traditional use of C. mexicana for stimulating sexual activity.

Differential effect of the 17ß-aminoestrogens prolame, butolame and pentolame in anxiety and depression models in rats.

Estrogens of clinical use produce consistent antidepressant- and anxiolytic-like effects in animal models of menopause. Regulation of the hypothalamic-pituitary-adrenal (HPA) or stress axis, has been proposed as a pathway through which estrogens improve affective-like behaviors. Anticoagulant 17ß-aminoestrogens (17ß-AEs) butolame and pentolame mimic some effects of estradiol (E2), i.e., on female rodent sexual behavior, with opposite actions on coagulation. However, their psychoactive actions have not been explored. On the basis of similitude with E2's effects, we hypothesized that these 17ß-AEs would induce anxiolytic- and antidepressant-like effects, which would be reflected in a reduction of activity in the HPA axis. In ovariectomized female rats, chronic treatment with prolame (60 µg/kg), butolame (65 µg/kg) and pentolame (70 µg/kg) reduced anxiety-like behavior in the elevated plus maze (evidenced by an increase in time in open arms, E2 (40 µg/kg) +176%; prolame +201%; butolame, +237%; and pentolame +295%, in comparison to the control vehicle group 100%). Pentolame also decreased significantly anxiety-like behavior in the burying behavior test. Prolame and E2 produced a significantly antidepressant-like action, which was not induced by butolame and pentolame. Behavioral effects of 17ß-AEs (and E2) on anxiety and depression did not follow the same pattern than corticosterone or E2 levels; they also were associated to changes in locomotor activity, evaluated by the open field test. These results constitute the first evidence of specific and selective actions of butolame and pentolame as anxiolytics for females with a hypoestrogenic condition. Results also confirm the potential of prolame as an antidepressant steroid with equivalent actions to E2. Psychoactive properties of 17ß-AEs in combinations with reduced adverse effects on coagulation, suggest that 17ß-AEs may be a good alternative replacement therapy for women with symptoms associated with menopause.

Influence of the brain sexual differentiation process on despair and antidepressant-like effect of fluoxetine in the rat forced swim test.

Sex differences exist in the depressive disorder prevalence and response to treatment. Several studies suggest that females respond better than males to the action of selective serotonin reuptake inhibitors (SSRIs), suggesting that gonadal hormones modulate mood and the response to these drugs. Sexual steroid hormones exert organizational actions (perennial and on early development) and activational effects (transient and on differentiated tissues). The aim of this study was to analyze sex differences in the forced swim test (FST) in animals without treatment and after fluoxetine (FLX, 0, 2.5, 5.0 and 10.0mg/kg). Initially, we compared male and female adult rats under control conditions or after altering their sexual differentiation process (at day 5 postnatally, PN, 60µg of testosterone propionate to females and male castration to induce or preclude masculinization, respectively). To further analyze if the sex differences depend on organizational or activational steroid hormone action we tested the same animals before and after adult gonadectomy. To prevent variations depending upon the estrous cycle, control and masculinized females were tested in estrus. Control females showed lower immobility and required lower doses of FLX (5mg/kg), to show an antidepressant-like effect, than males (10mg/kg), even after adult gonadectomy. In control males adult orchidectomy prevented FLX's action. Neonatally masculinized females exhibited analogous levels of immobility than control ones; before ovariectomy they responded to FLX similar to controls, but after the surgery they did not respond to fluoxetine. Neonatally orchidectomized males exhibited similar immobility values and response to FLX than control females. The findings suggest that the sex difference in despair depends on the hormones organizational effects and, in males, the response to FLX relies on organizational and activational actions.

Pro-sexual effects of Turnera diffusa Wild (Turneraceae) in male rats involves the nitric oxide pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Turnera diffusa Wild has been used in folk medicine by its aphrodisiac and tranquilizing properties. Previously we experimentally showed the aphrodisiac effect of a chemically characterized aqueous extract of Turnera diffusa in male rats. However, the mechanism of action underlying such effects has not been studied. STUDY AIMS: As part of our systematic studies of pharmacological properties of Turnera diffusa, we aimed to analyze whether the increased sexual motivation and the augmented sexual performance of sexually sluggish (SL) male rats treated with Turnera diffusa involves the NO pathway. Additionally we analyzed whether such effects were exerted at the level of the brain or the spinal cord. Finally, anxiety levels and ambulatory activity were also evaluated. MATERIAL AND METHODS: Turnera diffusa (10-40 mg/kg) and sildenafil citrate (10 mg/kg) with or without a nonspecific inhibitor of NO synthase, Nω-nitro-L-arginine methyl esther (L-NAME, 12.5 mg/kg) were evaluated in SL rats, in a standard sexual behavior test and in the fictive ejaculation model in spinal cord transected and urethane-anaesthetized SL rats. Anxiety levels or ambulation were assessed in the burying behavior and open-field tests. RESULTS: Turnera diffusa and sildenafil (both at 10 mg/kg) facilitated expression of male sexual behavior by shortening mainly ejaculation latency. Treatments also facilitated the number of discharges in the ejaculatory motor pattern as well as the number of ejaculatory motor patterns and its associated penile erections. L-NAME prevented the pro-sexual effects of treatments on both experimental models. Besides, the extract of Turnera diffusa (10 mg/kg) produced an anxiolytic-like effect in male rats without affecting ambulation. CONCLUSIONS: Findings from the present work support the notion that pro-sexual effect of the aqueous extract of Turnera diffusa in rats involves the participation of NO pathway, mainly at central level. The anxiolytic-like effect of Turnera diffusa is an advantage to its use for improving sexual performance.

Participation of estrogen receptors in the antidepressant-like effect of prolame on the forced swimming test.

Estrogen therapy may produce antidepressant-like actions, but the side effects, such as thromboembolic events, may restrict its use among women. The 17ß-aminoestrogens (AEs) [prolame [17ß-(3-hidroxy-1-propylamino)-1,3,5(10)-estratrien-3-ol)], butolame [17ß-(3-hidroxy-1-butylamino)-1,3,5(10)-estratrien-3-ol)], and pentolame [17ß-(5-hidroxy-1-pentylamino)-1,3,5(10)-estratrien-3-ol)] induce estrogenic and anticoagulant actions, effects that could prove advantageous in an estrogen therapy; however, their antidepressant-like effects have not been described. The objective of this study was to determine the effect of these 17ß-AEs (prolame, butolame and pentolame) in the forced swimming test (FST), an animal model sensitive to antidepressant drugs, and to establish the role of estrogen receptors in such actions. Ovariectomized female rats treated with prolame (10-200 µg/rat) showed a reduction in immobility and an increase in active behaviors in the FST, while this effect was not produced by butolame and pentolame (10-200 µg/rat). The antidepressant-like effect of prolame was similar to that of 17ß-estradiol (E2, 5-20 µg/rat), sharing with it a biphasic profile but at higher doses. Antidepressant-like actions of prolame and E2 were not associated with changes in locomotor activity. With respect to a control group tamoxifen (15 mg/kg) by itself produced no changes in all behavioral evaluations, but canceled the antidepressant-like effect of prolame and E2. It is concluded that estrogen receptors participate in antidepressant-like effect of both estrogens in the FST. Antidepressant-like activity of different AEs is discussed considering their differences in chemical structure and the schedule used. Our results show additional central actions of prolame besides its pro-sexual, anti-coagulant, estrogenic and anxiolytic activity.

Antidepressant-like effects of an alkaloid extract of the aerial parts of Annona cherimolia in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Several species of Annona (Annonaceae) are used in traditional Mexican medicine by their anti-anxiety, anticonvulsant and tranquilizing properties. It has been reported that the alkaloids isolated from some species of the Annona have affinity to serotonergic 5-HT(1A) receptors and modulate dopaminergic transmission, which is involved in depressive disorders. AIM OF THE STUDY: To investigate the antidepressant-like effect of an alkaloid extract from the aerial parts of Annona cherimola (TA) in mice. MATERIALS AND METHODS: The antidepressant-like effect was evaluated in the forced swimming test. To elucidate a possible mechanism of action, experiments of synergism with antidepressant drugs, such as imipramine (IMI), clomipramine (CLIMI), and fluoxetine (FLX), were carried out. The neurotransmitter content (DA: dopamine, 5HT: serotonin and its metabolites, HVA: homovanillic acid and 5HIAA: 5-hydroxyindoleacetic) in the whole brain of mice were also determined by HPLC method. TA chemical composition was determined using high performance liquid chromatography-electrospray mass spectrometry. RESULTS: The results showed that repeated treatment with TA produced antidepressant-like effects in mice. This effect was not related to an increase in locomotor activity. Administration of TA facilitated the antidepressant effect of IMI and CLIMI as well as increased the turnover of DA and 5-HT. The alkaloids: 1,2-dimethoxy-5,6,6a,7-tetrahydro-4H-dibenzoquinoline-3,8,9,10-tetraol, anonaine, liriodenine, and nornuciferine were the main constituents of TA. CONCLUSIONS: Results showed that TA produces an antidepressant-like action from a generalized increase in monominergic turnover, supporting the use in tradicional medicine of Annona cherimolia, and strongly suggest its therapeutic potency as an antidepressant agent.

Turnera diffusa Wild (Turneraceae) recovers sexual behavior in sexually exhausted males.

ETHNOPHARMACOLOGICAL RELEVANCE: In folk medicine, Turnera diffusa Wild (Turnera diffusa, Turneraceae) is considered as an aphrodisiac, but its ability to restore copulation in sexually inhibited subjects has not been reported. AIM OF THE STUDY: To determine whether Turnera diffusa recovers sexual behavior in sexually exhausted (SExh) male rats and to identify the main components in an aqueous extract. MATERIALS AND METHODS: SExh males were treated with Turnera diffusa, 20-80 mg/kg, yohimbine, 2 mg/kg, or vehicle. RESULTS: Yohimbine and Turnera diffusa (80 mg/kg) significantly increased the percentage of males achieving one ejaculatory series and resuming a second one. In addition, Turnera diffusa significantly reduced the post-ejaculatory interval. These effects were not associated to an increase in locomotor activity or anxiety-like behaviors. The HPLC-ESI-MS analysis showed the presence of caffeine, arbutine, and flavonoids as the main compounds in the active extract. CONCLUSION: The results support the use of Turnera diffusa as an aphrodisiac in traditional medicine and suggest possible therapeutic properties of Turnera diffusa on sexual dysfunction. The flavonoids present in active extract may participate in its pro-sexual effect, which is analogous to those produced by yohimbine, suggesting a shared mechanism of action.

Aging increases the susceptibility to develop anhedonia in male rats.

The objective of this study was to establish the effect of aging on the development of anhedonia, a core feature of depression. Young and old male Wistar rats (of around 3-5 and 12-15 months, respectively) were exposed to a chronic variable stress (CVS) schedule for 3 weeks. CVS produced anhedonia, indicated by a reduction in the intake of a sucrose solution (1%), in 8 out of 23 (35%) young rats and in 19 out of 26 (73%) old rats, implying that old animals are more susceptible to stress and develop anhedonia more readily than young animals. Young and old anhedonic rats showed a similar temporal course in the reduction of sucrose consumption, reaching the anhedonic state after 2 weeks of CVS exposure. Compared with young animals, old rats had lower basal serum testosterone and estradiol levels. The systemic levels of corticosterone did not vary between both age groups. No significant pathological condition was detected in old animals. It is suggested that the higher susceptibility to develop anhedonia in male rats could be associated to neuroendocrine changes consequent to aging.

Influence of inflammatory nociception on the anxiolytic-like effect of diazepam and buspirone in rats.

RATIONALE: The effect of anxiety on nociception has been evaluated but not that of nociception on anxiety. OBJECTIVE: The study was conducted to analyse the influence of nociception on basal levels of anxiety-like behaviour and on the action of anxiolytic drugs. METHODS: Nociception was induced by an intra-articular injection of uric acid at 3.75 or 7.5%. Experimental anxiety was determined in the rat burying behaviour and the elevated plus maze tests. To separate specific anxiety-related drug actions, a spontaneous ambulatory test was included. The anxiolytics, buspirone (2.5 and 5.0 mg/kg, i.p.) and diazepam (0.5, 1.0 and 2.0 mg/kg, i.p.), were used. RESULTS: In the nociception test, the pain-induced functional impairment rat model, uric acid at 3.75 and 7.5% had an effect of around 35 and 75%, respectively. Uric acid (UA) at the lower dose (3.75%) lacked an effect on burying behaviour but significantly increased the time spent and number of entries to the open arms; the higher UA dose (7.5%) produced a significant increase in the time spent and number of entries to the open arms and a statistically significant reduction in cumulative burying. Diazepam and buspirone produced a clear dose-dependent reduction in cumulative burying. In the plus maze, diazepam also induced an increase in the time spent and number of entries to the open arms. In the burying behaviour test, rats with a mild level of nociception (uric acid at 7.5%) were insensitive to the anxiolytic-like effect of these anxiolytic drugs. In the plus maze test, the anxiolytic-like effect of diazepam (1.0 mg/kg) was blocked under both levels of nociception. CONCLUSIONS: These data demonstrate that nociception modifies the response to anxiolytic drugs. The role of factors with anxiogenic properties produced during inflammation, which may modify diazepam and buspirone effects, is discussed.

Lateral septal neuronal firing rate increases during proestrus-estrus in the rat.

Neuronal activity of the lateral septal nucleus (LSN) is related to motivational and hedonic behavior. Even though some changes in mood and anxiety during proestrus and pregnancy have been reported, the possible changes in the neuronal activity of the LSN through the phases of the estrous cycle are unknown. In the present study we explored the neuronal activity from the LSN using glass micropipettes (NaCl 1 M, and Evans blue 2.5%; 3-8 Mohms in 30 urethane (1 g/kg) anesthetized Wistar rats. Analysis of data included a total of 88 single-unit extracellular recordings taken from the LSN during proestrus (n = 22), estrus (n = 23), diestrus (n = 22), and metestrus (n = 21). The highest values of firing rate were found in proestrus, and the lowest in metestrus, F(3,84) = 3.78, p < 0.01. During estrous cycles, in the phase characterized by high plasma levels of estradiol and progesterone, i.e., proestrus-estrus, the neurons from the dorsal aspect of the LSN fired at significantly (p < 0.05) higher frequencies, shorter first-order intervals and a lower coefficient of variation than those in the phase characterized by lower levels of estradiol and progesterone (metestrus-diestrus). In another group of rats (n = 12), immobility in the forced-swim test was assessed. Consistently, a longer latency (p < 0.05) for the first period of immobility and a nonsignificant trend to a lowered total time in immobility were found in proestrus and estrus. It is concluded that the higher firing rate in neurons from the dorsal aspect of the LSN during proestrus-estrus, may be associated with an increased motivation to escape from a stressful situation.

Interaction of desipramine with steroid hormones on experimental anxiety.

The present study analyzes if estradiol benzoate and/or progesterone interact with desmethylimipramine (DMI) to diminish experimental anxiety. The animal model of anxiety used was the conditioned defensive burying test. Dose response curves for DMI (0.625, 1.25 and 2.5 mg/kg, every 24 h, during 21 days), estradiol benzoate (0.5, 1.0, 2.0 and 4.0 micrograms/rat, 48 h) and progesterone (0.5, 1.0 and 2.0 mg/rat, -4 h) were made in ovariectomized rats. DMI per se decreased dose dependently the cumulative burying time, an effect considered as anxiolytic-like. Progesterone produced a decrease in burying at the highest dose, while estradiol benzoate had no effect on defensive burying. Both, progesterone (0.5 mg/rat) and estradiol benzoate (4.0 micrograms/rat) were able to decrease the cumulative burying behavior when injected with a subthreshold dose of DMI (1.25 mg/kg). In addition, the effect of DMI (1.25 mg/kg) plus the combination of estradiol benzoate and progesterone, sequentially administered (48 h and 4 h before the tests, respectively), also produced a synergistic decrease in burying behavior. In general, the treatments produced no changes in burying behavior latency, neither in spontaneous ambulation or in nociception. It is concluded that DMI synergizes its anxiolytic-like effect when administered with estradiol alone or in combination with progesterone. Present data provide experimental evidence suggesting an interaction between hormones and antidepressants. Results are discussed on the basis of the interaction between steroids and serotonergic or GABAergic receptors.

Progesterone reduces immobility in rats forced to swim.

BACKGROUND: Among its behavioral actions, progesterone reduces anxiety in several species including humans; however, any antidepressant-like properties remain to be explored. METHODS: In the present study, Wistar rats received injections (i.p.) of progesterone (0.20-3.0 mg/kg) 24 and 2 h before being submitted to the forced swim, a test in which antidepressants regularly reduce immobility and exert few or no actions on locomotor activity. In order to discard the cumulative effects of progesterone and a possible effect from the repetition of the swimming test, all animals received one of several progesterone doses in a different sequence following a completely randomized experimental intrasubject design. RESULTS: Ovariectomy did not modify immobility in the forced swim test as compared to control tests practiced before surgery. A dose of 0.80 mg/kg strongly reduced the total time of immobility in forced swim test (p < 0.001), but did not modify locomotor activity. In a drug-free control test applied 1 week after the last injection of progesterone, immobility returned to the higher values observed in the control tests. CONCLUSIONS: From these results, it is concluded that progesterone may possess some anti-depressant-like activity.

Chronic treatment with desipramine induces an estrous cycle-dependent anxiolytic-like action in the burying behavior, but not in the elevated plus-maze test.

The effect of chronic desipramine (DMI, 2.5 mg/kg x 21-26 days) treatment in female rats in two anxiety paradigms was assessed: the burying behavior (BB) and the elevated plus-maze (EPM) tests. In the BB test DMI produced a significant decrease in burying in ovariectomized rats, an effect considered as anxiolytic-like. In cycling females, DMI also reduced the cumulative BB most notably in proestrus rats. However, in diestrus rats no anxiolytic-like actions were observed. In addition, DMI increased BB latencies in proestrus and estrus rats. In the EPM test, DMI produced anxiolytic-like actions only in ovariectomized rats, while no significant actions were found in cycling females. Finally, the chronic treatment with DMI produced a general reduction in the ambulatory behavior of rats in all estrous cycle phases. Results are discussed on the basis of the differences between both anxiety paradigms and the probable relationship between the steroids secreted during proestrus and chronic DMI treatment.

Desipramine restricts estral cycle oscillations in swimming.

1. Desipramine (DMI) is a tricyclic antidepressant which reduces the immobility in rats forced to swim; however, it is unknown whether estral cycle phases impinge on DMI actions on immobility in daily swimming tests during several weeks. 2. In female wistar rats, vaginal smears taken before testing defined four estral phases. Afterwards, the authors assessed the latency for the first period of immobility in five-min forced swim tests practiced on 21-day DMI (DMI group), 21-day washout saline given after a 21-day DMI treatment (washout-saline group), or non-treated rats (control group). 3. We observed a longer latency for the first period of immobility in proestrus-estrus from the control and washout-saline groups. The 21-day treatment with DMI (2.1 mg/kg i.p., once a day) significantly (p < 0.001) increased the latency by about 160% from control regardless of the estral cycle phase. 4. It is concluded that proestrus-estrus relates to increased struggling behavior. DMI enhances struggling behavior independently of hormonal state.

Crude preparations of Dioon spinulosum dyer neurotoxicity: methylazoxymethanol produces petil mal seizures in susceptible individuals.

Dioon spinulosum is a cycad prepared as an alternative food and consumed by Chinantecos from Veracruz and Oaxaca, México. Whether Dioon spinulosum possesses neurotoxic properties is unknown, therefore, we used wistar rats receiving several regimens of D. spinulosum. Semi-liquid diarrhea followed the ingestion of crude kernels of D. spinulosum (group-1). In group-2 we offered during 10 days, purine and water during 12 h/day, and kernel or sclerotesta during the remaining 12 h (8.00 p.m. to 8.00 a.m.). As a result, a significantly decreased ingestion of water and cycad was compensated by a higher ingestion of purine and water during the period for which they had access to their normal diet. In group-3 which received lyophilized powdered crude kernel through a displaceable oesophagic cannula during 80 days, the locomotor activity was significantly lowered (p<0.05), but their fine motor ability for swimming remained unaltered. In this group, the computerized analysis of the electroencephalogram illustrated a dominance of high-voltage, high-frequency waves as compared to a matched-age control group (p<0.05). In group-4, the active toxin of cycads, methylazoxymethanol-glucoside applied directly to the cerebral cortex (1 µl), produced an epileptic status (spike-wave activity: 3-6 Hz/200 µV) lasting more than six hours in 30% of the animals. In conclusion, D. spinulosum produced a decrease in gross locomotor activity, and an increased excitability of the central nervous system.