The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
Carlos M. Contreras - One of the best experts on this subject based on the ideXlab platform.
-
Estrogen and progesterone priming induces lordosis in female rats by reversing the inhibitory influence of the infralimbic cortex on neuronal activity of the Lateral Septal Nucleus.
Neuroscience letters, 2020Co-Authors: Carlos M. Contreras, Ana G. Gutiérrez-garcíaAbstract:Abstract The Lateral Septal Nucleus (LSN) exerts inhibitory control over lordosis in female rats, but the influence of forebrain structures, such as prelimbic (PL) and infralimbic (IL) regions of the medial prefrontal cortex (mPFC), on LSN activity during sexual receptivity is unknown. We hypothesized that the neural responsivity of these connections may differ depending on sexual receptivity. Gonadally intact female Wistar rats received sequential priming injections of estradiol and progesterone (E2-P4). The presence of lordosis was then confirmed by exposing the female rats to a sexually experienced male rat. Intromission was not allowed. Vaginal smear analyses verified that the rats were in proestrus-estrus of the estrous cycle. The results were compared with a diestrus group, which was verified by vaginal smears and the absence of lordosis. Under ethyl-carbamate anesthesia, single-unit extracellular recordings of the LSN were performed during electrical stimulation of the PL and IL to evaluate possible changes in the responsivity of neural connections. Stimulation of the PL or IL produced a short-latency, brief-duration (paucisynaptic) excitatory response in the LSN, followed by a period of afterhyperpolarization. Responsivity of the PL-LSN pathway was unaffected by E2-P4 priming. The paucisynaptic response of the IL-LSN pathway was significantly greater in the E2-P4-primed group than in the diestrus group, and the afterhyperpolarization response decreased to nearly zero. These findings indicate that the IL exerts inhibitory control over the LSN during diestrus in rats, but this inhibitory control decreases under the action of gonadal steroids, seemingly favoring sexual receptivity.
-
Fluoxetine and stress inversely modify Lateral Septal Nucleus-mpfc neuronal responsivity.
Behavioural brain research, 2018Co-Authors: Carlos M. Contreras, Ana G. Gutiérrez-garcía, José Armando Sánchez-salcedoAbstract:Abstract Several clinically effective antidepressants increase the neuronal firing rate in the Lateral Septal Nucleus (LSN), a forebrain structure that is anatomically related to medial prefrontal cortex (mPFC) regions. mPFC function is related to depression and the regulation of fear. However, unknown is whether antidepressant treatment or chronic stress modifies the responsivity of neuronal LSN-mPFC connections. We performed single-unit extracellular recordings in the anterior cingulate cortex (ACC) and prelimbic (PL) and infralimbic (IL) regions of the mPFC during stimulation of the LSN in anesthetized male Wistar rats that received fluoxetine (1 mg/kg, 21 days) or were subjected to chronic mild stress (5 weeks). The results were compared with a control group (saline treatment, devoid of behavioral manipulations). Stimulation of the LSN produced an initial excitatory paucisynaptic response, followed by an afterdischarge, characterized by an increase in the neuronal firing rate. Opposite changes were induced by fluoxetine treatment and chronic stress exposure. Peristimulus histograms and unit-activity ratio analyses indicated that LSN-mPFC responsivity differed between fluoxetine treatment and chronic stress exposure. Fluoxetine reduced neuronal responsivity in the LSN-PL and LSN-IL, and stress increased neuronal responsivity in the same regions. In both cases, the changes were more pronounced in the IL region. The lower responsivity of LSN-PL and LSN-IL connections that was produced by fluoxetine may reflect a higher threshold for fear, and lower responsivity of this connection may be related to states of fear. The LSN and mPFC comprise a portion of a limbic-cortical circuit where neuronal responses depend on specific conditions.
-
Widespread blunting of hypothalamic and amygdala-Septal activity and behavior in rats with long-term hyperglycemia
Behavioural brain research, 2016Co-Authors: María Luisa Moreno-cortés, Gabriel Guillén-ruiz, Ana G. Gutiérrez-garcía, T. Romo-gonzález, Carlos M. ContrerasAbstract:Abstract Anxiety and depression in diabetic patients contributes to a poor prognosis, but possible causal relationships have been controversial. Anxiety, fear, and anhedonia are mediated by interactions between different deep structures of the temporal lobe (e.g., amygdala complex and hippocampus) and other forebrain-related structures (e.g., Lateral Septal Nucleus). Connections between these structures and the hypothalamic orexinergic system are necessary for the maintenance of energy and wakefulness. However, few studies have explored the impact of long-term hyperglycemia in these structures on anxiety. We induced long-term hyperglycemia (glucose levels of ∼500 mg/dl) in Wistar rats by injecting them with alloxan and simultaneously protecting them from hyperglycemia by injecting them daily with a low dose of insulin (i.e., just enough insulin to avoid death), thus maintaining hyperglycemia and ketonuria for as long as 6 weeks. Compared with controls, long-term hyperglycemic rats exhibited a significant reduction of Fos expression in the Lateral Septal Nucleus and basoLateral amygdala, but no differences were found in cerebellar regions. Orexin-A cells appeared to be inactive in the Lateral hypothalamus. No differences were found in sucrose consumption or behavior in the elevated plus maze compared with the control group, but a decrease in general locomotion was observed. These data indicate a generalized blunting of the metabolic brain response, accompanied by a decrease in locomotion but no changes in hedonic- or anxiety-like behavior.
-
P03-109 - Involvement of the Lateral Septal Nucleus and GABAa receptors in the antidepressant-like effects of allopregnanolone in wistar rats
European Psychiatry, 2011Co-Authors: Juan Francisco Rodríguez-landa, Carlos M. Contreras, Blandina Bernal-morales, Ana G. Gutiérrez-garcía, Rosa Isela García-ríosAbstract:Introduction Pharmacological and non-pharmacological antidepressant therapies increase the firing rate of Lateral Septal Nucleus neurons (a brain structure involved in mood state regulation) and reduce immobility in the forced swim test (FST), whereas the neurosteroid allopregnanolone appears to produce antidepressant-like effects through actions at GABAA receptors. Objective To explore the participation of the Lateral Septal Nucleus and GABAA receptors in the antidepressant-like effects of allopregnanolone in Wistar rats. Methods First, the minimally effective dose of allopregnanolone that produces antidepressant-like effects in the FST was determined. Second, the effect of this minimally effective dose in the FST was evaluated on the firing rate of Lateral Septal neurons. Third, the antidepressant-like effects of microinjection of allopregnanolone (1.0 μg/rat) into the Lateral Septal Nucleus was evaluated in the FST. Fourth, we explored whether the effects of allopregnanolone on the Lateral Septal neuron firing rate and FST are blocked by picrotoxin or bicuculline, two GABAA receptor antagonists. Results The minimally effective dose of allopregnanolone with antidepressant-like effects in the FST was 1.0 mg/kg (i.p.) and significantly increased the firing rate of Lateral Septal neurons. Microinjection of allopregnanolone into the Lateral Septal Nucleus produced antidepressant-like effects in the FST. Pretreatment with picrotoxin and bicuculline blocked the increase in Lateral Septal neuron firing rate and the antidepressant-like effects of allopregnanolone in the FST. Conclusion The Lateral Septal Nucleus participates in the antidepressant-like effects of allopregnanolone through actions on GABAA receptors in Wistar rats.
-
Changes in Lateral Septal Nucleus neuron firing rate and coping with forced swim during gestation in the Wistar rat
Animal Behaviour, 2008Co-Authors: Carlos M. Contreras, Juan Francisco Rodríguez-landa, Blandina Bernal-morales, Ana G. Gutiérrez-garcía, Daniel Muñoz-lópezAbstract:The aim of the present study was to explore changes in immobility during the forced-swim test (FST) and in the firing rate of the Lateral Septal Nucleus (LSN) during gestation (G) in the Wistar rat, Rattus norvegicus. In the latter test we also measured changes in plasma progesterone levels. In the FST we considered total time of immobility and also the angle formed by the longitudinal axis of the rat's body and the water surface during immobility. Total time of immobility progressively diminished along gestation at the expense of a decrease in immobility at the 0–30° angle. Immobility at 45 to 90° paralleled body weight gain, but locomotion in the open-field test did not change along gestation. The LSN firing rate increased progressively from day G1 to day G7, peaking significantly on G14 and decreasing to dioestrus levels by G19 and postpartum. Finally, plasma progesterone peaked significantly on G14 and G19, compared with dioestrus, G1, G7 and postpartum. Because clinically effective antidepressants as well as progesterone reduce immobility in FST and increase firing rate in the LSN, and both effects were observed during gestation but with different timing, we conclude that the smooth increase in plasma progesterone and the LSN firing rate peak at G14 may lead to additional changes that allow rats to cope with the stress represented by FST during the second third of gestation and postpartum.
Ana G. Gutiérrez-garcía - One of the best experts on this subject based on the ideXlab platform.
-
Estrogen and progesterone priming induces lordosis in female rats by reversing the inhibitory influence of the infralimbic cortex on neuronal activity of the Lateral Septal Nucleus.
Neuroscience letters, 2020Co-Authors: Carlos M. Contreras, Ana G. Gutiérrez-garcíaAbstract:Abstract The Lateral Septal Nucleus (LSN) exerts inhibitory control over lordosis in female rats, but the influence of forebrain structures, such as prelimbic (PL) and infralimbic (IL) regions of the medial prefrontal cortex (mPFC), on LSN activity during sexual receptivity is unknown. We hypothesized that the neural responsivity of these connections may differ depending on sexual receptivity. Gonadally intact female Wistar rats received sequential priming injections of estradiol and progesterone (E2-P4). The presence of lordosis was then confirmed by exposing the female rats to a sexually experienced male rat. Intromission was not allowed. Vaginal smear analyses verified that the rats were in proestrus-estrus of the estrous cycle. The results were compared with a diestrus group, which was verified by vaginal smears and the absence of lordosis. Under ethyl-carbamate anesthesia, single-unit extracellular recordings of the LSN were performed during electrical stimulation of the PL and IL to evaluate possible changes in the responsivity of neural connections. Stimulation of the PL or IL produced a short-latency, brief-duration (paucisynaptic) excitatory response in the LSN, followed by a period of afterhyperpolarization. Responsivity of the PL-LSN pathway was unaffected by E2-P4 priming. The paucisynaptic response of the IL-LSN pathway was significantly greater in the E2-P4-primed group than in the diestrus group, and the afterhyperpolarization response decreased to nearly zero. These findings indicate that the IL exerts inhibitory control over the LSN during diestrus in rats, but this inhibitory control decreases under the action of gonadal steroids, seemingly favoring sexual receptivity.
-
Fluoxetine and stress inversely modify Lateral Septal Nucleus-mpfc neuronal responsivity.
Behavioural brain research, 2018Co-Authors: Carlos M. Contreras, Ana G. Gutiérrez-garcía, José Armando Sánchez-salcedoAbstract:Abstract Several clinically effective antidepressants increase the neuronal firing rate in the Lateral Septal Nucleus (LSN), a forebrain structure that is anatomically related to medial prefrontal cortex (mPFC) regions. mPFC function is related to depression and the regulation of fear. However, unknown is whether antidepressant treatment or chronic stress modifies the responsivity of neuronal LSN-mPFC connections. We performed single-unit extracellular recordings in the anterior cingulate cortex (ACC) and prelimbic (PL) and infralimbic (IL) regions of the mPFC during stimulation of the LSN in anesthetized male Wistar rats that received fluoxetine (1 mg/kg, 21 days) or were subjected to chronic mild stress (5 weeks). The results were compared with a control group (saline treatment, devoid of behavioral manipulations). Stimulation of the LSN produced an initial excitatory paucisynaptic response, followed by an afterdischarge, characterized by an increase in the neuronal firing rate. Opposite changes were induced by fluoxetine treatment and chronic stress exposure. Peristimulus histograms and unit-activity ratio analyses indicated that LSN-mPFC responsivity differed between fluoxetine treatment and chronic stress exposure. Fluoxetine reduced neuronal responsivity in the LSN-PL and LSN-IL, and stress increased neuronal responsivity in the same regions. In both cases, the changes were more pronounced in the IL region. The lower responsivity of LSN-PL and LSN-IL connections that was produced by fluoxetine may reflect a higher threshold for fear, and lower responsivity of this connection may be related to states of fear. The LSN and mPFC comprise a portion of a limbic-cortical circuit where neuronal responses depend on specific conditions.
-
Widespread blunting of hypothalamic and amygdala-Septal activity and behavior in rats with long-term hyperglycemia
Behavioural brain research, 2016Co-Authors: María Luisa Moreno-cortés, Gabriel Guillén-ruiz, Ana G. Gutiérrez-garcía, T. Romo-gonzález, Carlos M. ContrerasAbstract:Abstract Anxiety and depression in diabetic patients contributes to a poor prognosis, but possible causal relationships have been controversial. Anxiety, fear, and anhedonia are mediated by interactions between different deep structures of the temporal lobe (e.g., amygdala complex and hippocampus) and other forebrain-related structures (e.g., Lateral Septal Nucleus). Connections between these structures and the hypothalamic orexinergic system are necessary for the maintenance of energy and wakefulness. However, few studies have explored the impact of long-term hyperglycemia in these structures on anxiety. We induced long-term hyperglycemia (glucose levels of ∼500 mg/dl) in Wistar rats by injecting them with alloxan and simultaneously protecting them from hyperglycemia by injecting them daily with a low dose of insulin (i.e., just enough insulin to avoid death), thus maintaining hyperglycemia and ketonuria for as long as 6 weeks. Compared with controls, long-term hyperglycemic rats exhibited a significant reduction of Fos expression in the Lateral Septal Nucleus and basoLateral amygdala, but no differences were found in cerebellar regions. Orexin-A cells appeared to be inactive in the Lateral hypothalamus. No differences were found in sucrose consumption or behavior in the elevated plus maze compared with the control group, but a decrease in general locomotion was observed. These data indicate a generalized blunting of the metabolic brain response, accompanied by a decrease in locomotion but no changes in hedonic- or anxiety-like behavior.
-
P03-109 - Involvement of the Lateral Septal Nucleus and GABAa receptors in the antidepressant-like effects of allopregnanolone in wistar rats
European Psychiatry, 2011Co-Authors: Juan Francisco Rodríguez-landa, Carlos M. Contreras, Blandina Bernal-morales, Ana G. Gutiérrez-garcía, Rosa Isela García-ríosAbstract:Introduction Pharmacological and non-pharmacological antidepressant therapies increase the firing rate of Lateral Septal Nucleus neurons (a brain structure involved in mood state regulation) and reduce immobility in the forced swim test (FST), whereas the neurosteroid allopregnanolone appears to produce antidepressant-like effects through actions at GABAA receptors. Objective To explore the participation of the Lateral Septal Nucleus and GABAA receptors in the antidepressant-like effects of allopregnanolone in Wistar rats. Methods First, the minimally effective dose of allopregnanolone that produces antidepressant-like effects in the FST was determined. Second, the effect of this minimally effective dose in the FST was evaluated on the firing rate of Lateral Septal neurons. Third, the antidepressant-like effects of microinjection of allopregnanolone (1.0 μg/rat) into the Lateral Septal Nucleus was evaluated in the FST. Fourth, we explored whether the effects of allopregnanolone on the Lateral Septal neuron firing rate and FST are blocked by picrotoxin or bicuculline, two GABAA receptor antagonists. Results The minimally effective dose of allopregnanolone with antidepressant-like effects in the FST was 1.0 mg/kg (i.p.) and significantly increased the firing rate of Lateral Septal neurons. Microinjection of allopregnanolone into the Lateral Septal Nucleus produced antidepressant-like effects in the FST. Pretreatment with picrotoxin and bicuculline blocked the increase in Lateral Septal neuron firing rate and the antidepressant-like effects of allopregnanolone in the FST. Conclusion The Lateral Septal Nucleus participates in the antidepressant-like effects of allopregnanolone through actions on GABAA receptors in Wistar rats.
-
Changes in Lateral Septal Nucleus neuron firing rate and coping with forced swim during gestation in the Wistar rat
Animal Behaviour, 2008Co-Authors: Carlos M. Contreras, Juan Francisco Rodríguez-landa, Blandina Bernal-morales, Ana G. Gutiérrez-garcía, Daniel Muñoz-lópezAbstract:The aim of the present study was to explore changes in immobility during the forced-swim test (FST) and in the firing rate of the Lateral Septal Nucleus (LSN) during gestation (G) in the Wistar rat, Rattus norvegicus. In the latter test we also measured changes in plasma progesterone levels. In the FST we considered total time of immobility and also the angle formed by the longitudinal axis of the rat's body and the water surface during immobility. Total time of immobility progressively diminished along gestation at the expense of a decrease in immobility at the 0–30° angle. Immobility at 45 to 90° paralleled body weight gain, but locomotion in the open-field test did not change along gestation. The LSN firing rate increased progressively from day G1 to day G7, peaking significantly on G14 and decreasing to dioestrus levels by G19 and postpartum. Finally, plasma progesterone peaked significantly on G14 and G19, compared with dioestrus, G1, G7 and postpartum. Because clinically effective antidepressants as well as progesterone reduce immobility in FST and increase firing rate in the LSN, and both effects were observed during gestation but with different timing, we conclude that the smooth increase in plasma progesterone and the LSN firing rate peak at G14 may lead to additional changes that allow rats to cope with the stress represented by FST during the second third of gestation and postpartum.
Juan Francisco Rodríguez-landa - One of the best experts on this subject based on the ideXlab platform.
-
Long-term ovariectomy increases anxiety- and despair-like behaviors associated with lower Fos immunoreactivity in the Lateral Septal Nucleus in rats.
Behavioural brain research, 2018Co-Authors: Abraham Puga-olguín, Juan Francisco Rodríguez-landa, María De Jesús Rovirosa-hernández, León Jesús German-ponciano, Mario Caba, Enrique Meza, Gabriel Guillén-ruiz, Oscar Jerónimo Olmos-vázquezAbstract:In woman, surgical menopause is associated with anxiety and depression symptoms. Ovariectomy in rats has been proposed as an experimental model of surgical menopause, but its long-term effects on anxiety- and depression-like behaviors and relationship with cellular changes in specific brain structures are unknown. The effects of ovariectomy on anxiety- and despair-like behavior 1, 3, 6, 9, 12, and 15-weeks postovariectomy were evaluated. Fos-immunoreactivity was evaluated in the Lateral Septal Nucleus (LSN). The effects were compared with rats in the proestrus-estrus and metestrus-diestrus phases of the ovarian cycle and with ovariectomized rats that received 17β-estradiol (OVXE). Three weeks postovariectomy, the rats exhibited an increase in anxiety-like behavior compared with PE and OVXE groups. Decreases in the locomotor activity and time spent grooming and rearing were detected in all the ovariectomized rats. In the forced swim test, the rats exhibited an increase in immobility time 6-weeks postovariectomy compared with control groups. The Fos-immunoreactivity in the LSN was significantly lower in all groups of ovariectomized rats compared with control groups. These findings indicate that rats develop anxiety-like behavior 3-weeks postovariectomy. Six weeks postovariectomy, the rats also developed despair-like behavior, which was associated with a reduction of Fos immunoreactivity in the LSN. Long-term ovariectomy may be considered a useful tool for understanding the development of neurobiological changes associated with surgical menopause. This model may also be useful for evaluating potential anxiolytic and antidepressant effects of diverse substances to ameliorate typical emotional and affective disorders during surgical menopause in women.
-
P03-109 - Involvement of the Lateral Septal Nucleus and GABAa receptors in the antidepressant-like effects of allopregnanolone in wistar rats
European Psychiatry, 2011Co-Authors: Juan Francisco Rodríguez-landa, Carlos M. Contreras, Blandina Bernal-morales, Ana G. Gutiérrez-garcía, Rosa Isela García-ríosAbstract:Introduction Pharmacological and non-pharmacological antidepressant therapies increase the firing rate of Lateral Septal Nucleus neurons (a brain structure involved in mood state regulation) and reduce immobility in the forced swim test (FST), whereas the neurosteroid allopregnanolone appears to produce antidepressant-like effects through actions at GABAA receptors. Objective To explore the participation of the Lateral Septal Nucleus and GABAA receptors in the antidepressant-like effects of allopregnanolone in Wistar rats. Methods First, the minimally effective dose of allopregnanolone that produces antidepressant-like effects in the FST was determined. Second, the effect of this minimally effective dose in the FST was evaluated on the firing rate of Lateral Septal neurons. Third, the antidepressant-like effects of microinjection of allopregnanolone (1.0 μg/rat) into the Lateral Septal Nucleus was evaluated in the FST. Fourth, we explored whether the effects of allopregnanolone on the Lateral Septal neuron firing rate and FST are blocked by picrotoxin or bicuculline, two GABAA receptor antagonists. Results The minimally effective dose of allopregnanolone with antidepressant-like effects in the FST was 1.0 mg/kg (i.p.) and significantly increased the firing rate of Lateral Septal neurons. Microinjection of allopregnanolone into the Lateral Septal Nucleus produced antidepressant-like effects in the FST. Pretreatment with picrotoxin and bicuculline blocked the increase in Lateral Septal neuron firing rate and the antidepressant-like effects of allopregnanolone in the FST. Conclusion The Lateral Septal Nucleus participates in the antidepressant-like effects of allopregnanolone through actions on GABAA receptors in Wistar rats.
-
Changes in Lateral Septal Nucleus neuron firing rate and coping with forced swim during gestation in the Wistar rat
Animal Behaviour, 2008Co-Authors: Carlos M. Contreras, Juan Francisco Rodríguez-landa, Blandina Bernal-morales, Ana G. Gutiérrez-garcía, Daniel Muñoz-lópezAbstract:The aim of the present study was to explore changes in immobility during the forced-swim test (FST) and in the firing rate of the Lateral Septal Nucleus (LSN) during gestation (G) in the Wistar rat, Rattus norvegicus. In the latter test we also measured changes in plasma progesterone levels. In the FST we considered total time of immobility and also the angle formed by the longitudinal axis of the rat's body and the water surface during immobility. Total time of immobility progressively diminished along gestation at the expense of a decrease in immobility at the 0–30° angle. Immobility at 45 to 90° paralleled body weight gain, but locomotion in the open-field test did not change along gestation. The LSN firing rate increased progressively from day G1 to day G7, peaking significantly on G14 and decreasing to dioestrus levels by G19 and postpartum. Finally, plasma progesterone peaked significantly on G14 and G19, compared with dioestrus, G1, G7 and postpartum. Because clinically effective antidepressants as well as progesterone reduce immobility in FST and increase firing rate in the LSN, and both effects were observed during gestation but with different timing, we conclude that the smooth increase in plasma progesterone and the LSN firing rate peak at G14 may lead to additional changes that allow rats to cope with the stress represented by FST during the second third of gestation and postpartum.
-
Intraaccumbens dopaminergic lesion suppresses desipramine effects in the forced swim test but not in the neuronal activity of Lateral Septal Nucleus.
Progress in Neuro-psychopharmacology & Biological Psychiatry, 2003Co-Authors: Ana G. Gutiérrez-garcía, Juan Francisco Rodríguez-landa, Carlos M. Contreras, Blandina Bernal-morales, José Luis Dı́az-meza, Margarita SaavedraAbstract:The Nucleus accumbens (NAcc) function is related to locomotor activity, while the Lateral Septal Nucleus (LSN) is related to the motivational aspects of behavior. Thus, a dopaminergic lesion of the NAcc blocks the antiimmobility effect of desipramine (DMI) and this tricyclic increases the firing rate of the LSN; however, it is unknown whether a relation exists between a dopaminergic lesion of the NAcc and the response of LSN neurons to DMI treatment. Therefore, we conducted a longitudinal study to further explore the participation of NAcc dopaminergic terminals in the immobility reduction exerted by DMI in the forced swim test and its relation to the firing rate of the LSN, at the same time exploring motor and motivational aspects of DMI–dopaminergic relationships in the animals. A dopaminergic lesion was biLaterally produced by 6-hydroxydopamine (6-OHDA) injection into the NAcc of adult ovariectomized Wistar rats pretreated with DMI (25 mg/kg ip, 30 min before lesion to protect NA terminals but to destroy DA endings). Treatments with DMI or saline began 24 h after stereotaxic surgery. The results showed that DMI once a day during 9 days (10 mg/kg) reduced immobility in the forced swim test in the sham-lesion group (P
-
The lowest effective dose of fluoxetine in the forced swim test significantly affects the firing rate of Lateral Septal Nucleus neurones in the rat
Journal of psychopharmacology (Oxford England), 2001Co-Authors: Carlos M. Contreras, Juan Francisco Rodríguez-landa, Ana G. Gutiérrez-garcía, Blandina Bernal-moralesAbstract:The administration of a relatively high dose of antidepressant drugs produces an increased neuronal firing rate of the Lateral Septal Nucleus (LSN) in the rat and a decreased immobility in rats forced to swim. However, it is unknown whether a minimally effective low-dose 21-day treatment with the selective serotonin reuptake inhibitor, fluoxetine, while reducing immobility in the forced swim test, also increases the neuronal firing rate of the LSN in Wistar rats. The total time of immobility decreased with a daily injection of 0.5, 1.0 or 2.0 mg/kg of fluoxetine (p < 0.001), and the lowest dose increasing the latency to the first immobility period (p < 0.0001) was 1.0 mg/kg. Therefore, the action of the 21-day fluoxetine treatment (1.0 mg/kg) on the firing rate of LSN neurones was tested in another group of rats. A total amount of 78 single-unit extracellular recordings was taken from the LSN of eight control rats (n = 40) and eight fluoxetine treated rats (n = 38). The LSN firing rate in the fluoxetine group was double (18.3 +/- 2.5 spikes per 10 s, p < 0.05) that in the control group (7.0 +/- 0.9 spikes per 10 s), and the first order interval of firing proved to be significantly lower in the fluoxetine group compared to the control group (384.3 +/- 22.3 and 639.7 +/- 27.5 ms, respectively; p < 0.05). In conclusion, the increased neuronal tiring rate of the LSN in the animals treated with a low dose of fluoxetine may be associated with an increased motivation to escape from the stressful situation that the forced swim represents.
Margarita Saavedra - One of the best experts on this subject based on the ideXlab platform.
-
Intraaccumbens dopaminergic lesion suppresses desipramine effects in the forced swim test but not in the neuronal activity of Lateral Septal Nucleus.
Progress in Neuro-psychopharmacology & Biological Psychiatry, 2003Co-Authors: Ana G. Gutiérrez-garcía, Juan Francisco Rodríguez-landa, Carlos M. Contreras, Blandina Bernal-morales, José Luis Dı́az-meza, Margarita SaavedraAbstract:The Nucleus accumbens (NAcc) function is related to locomotor activity, while the Lateral Septal Nucleus (LSN) is related to the motivational aspects of behavior. Thus, a dopaminergic lesion of the NAcc blocks the antiimmobility effect of desipramine (DMI) and this tricyclic increases the firing rate of the LSN; however, it is unknown whether a relation exists between a dopaminergic lesion of the NAcc and the response of LSN neurons to DMI treatment. Therefore, we conducted a longitudinal study to further explore the participation of NAcc dopaminergic terminals in the immobility reduction exerted by DMI in the forced swim test and its relation to the firing rate of the LSN, at the same time exploring motor and motivational aspects of DMI–dopaminergic relationships in the animals. A dopaminergic lesion was biLaterally produced by 6-hydroxydopamine (6-OHDA) injection into the NAcc of adult ovariectomized Wistar rats pretreated with DMI (25 mg/kg ip, 30 min before lesion to protect NA terminals but to destroy DA endings). Treatments with DMI or saline began 24 h after stereotaxic surgery. The results showed that DMI once a day during 9 days (10 mg/kg) reduced immobility in the forced swim test in the sham-lesion group (P
-
intraaccumbens dopaminergic lesion suppresses desipramine effects in the forced swim test but not in the neuronal activity of Lateral Septal Nucleus
Progress in Neuro-psychopharmacology & Biological Psychiatry, 2003Co-Authors: Ana G Gutierrezgarcia, Carlos M. Contreras, Juan Francisco Rodriguezlanda, Blandina Bernalmorales, Jose Luis Diazmeza, Margarita SaavedraAbstract:The Nucleus accumbens (NAcc) function is related to locomotor activity, while the Lateral Septal Nucleus (LSN) is related to the motivational aspects of behavior. Thus, a dopaminergic lesion of the NAcc blocks the antiimmobility effect of desipramine (DMI) and this tricyclic increases the firing rate of the LSN; however, it is unknown whether a relation exists between a dopaminergic lesion of the NAcc and the response of LSN neurons to DMI treatment. Therefore, we conducted a longitudinal study to further explore the participation of NAcc dopaminergic terminals in the immobility reduction exerted by DMI in the forced swim test and its relation to the firing rate of the LSN, at the same time exploring motor and motivational aspects of DMI-dopaminergic relationships in the animals. A dopaminergic lesion was biLaterally produced by 6-hydroxydopamine (6-OHDA) injection into the NAcc of adult ovariectomized Wistar rats pretreated with DMI (25 mg/kg ip, 30 min before lesion to protect NA terminals but to destroy DA endings). Treatments with DMI or saline began 24 h after stereotaxic surgery. The results showed that DMI once a day during 9 days (10 mg/kg) reduced immobility in the forced swim test in the sham-lesion group (P<.02); however, in the dopaminergic lesion group submitted to DMI treatment, immobility remained at control level in agreement with other reports. DMI increased the firing rate of the LSN (P<.001) independently of the 6-OHDA lesion. In conclusion, the dopaminergic terminals of the NAcc seem to be essential for the motor manifestation associated with motivation induced by DMI in the forced swim test, given that the antiimmobility actions of DMI are blocked after a dopaminergic NAcc lesion; however, the effect on the firing rate of LSN neurons is still present.
-
an early lesion of the Lateral Septal nuclei produces changes in the forced swim test depending on gender
Progress in Neuro-psychopharmacology & Biological Psychiatry, 1995Co-Authors: Carlos M. Contreras, Margarita Saavedra, Horacio Laramorales, Miguel Molinahernandez, Gerardo ArrellinrosasAbstract:Abstract 1. 1. Several pharmacological maneuvers in very young rats produce later changes resembling human depression. 2. 2. Rats were submitted to a wide lesion in Lateral Septal region at 8th day after birth and forced to swim at maturity. 3. 3. Male lesioned group showed the highest amount of immobility; whereas, female sham lesion group showed a greater response to treatments. 4. 4. A gender-dependent sensitivity to early Lateral Septal Nucleus lesions and to antidepressants are concluded.
Blandina Bernalmorales - One of the best experts on this subject based on the ideXlab platform.
-
intraaccumbens dopaminergic lesion suppresses desipramine effects in the forced swim test but not in the neuronal activity of Lateral Septal Nucleus
Progress in Neuro-psychopharmacology & Biological Psychiatry, 2003Co-Authors: Ana G Gutierrezgarcia, Carlos M. Contreras, Juan Francisco Rodriguezlanda, Blandina Bernalmorales, Jose Luis Diazmeza, Margarita SaavedraAbstract:The Nucleus accumbens (NAcc) function is related to locomotor activity, while the Lateral Septal Nucleus (LSN) is related to the motivational aspects of behavior. Thus, a dopaminergic lesion of the NAcc blocks the antiimmobility effect of desipramine (DMI) and this tricyclic increases the firing rate of the LSN; however, it is unknown whether a relation exists between a dopaminergic lesion of the NAcc and the response of LSN neurons to DMI treatment. Therefore, we conducted a longitudinal study to further explore the participation of NAcc dopaminergic terminals in the immobility reduction exerted by DMI in the forced swim test and its relation to the firing rate of the LSN, at the same time exploring motor and motivational aspects of DMI-dopaminergic relationships in the animals. A dopaminergic lesion was biLaterally produced by 6-hydroxydopamine (6-OHDA) injection into the NAcc of adult ovariectomized Wistar rats pretreated with DMI (25 mg/kg ip, 30 min before lesion to protect NA terminals but to destroy DA endings). Treatments with DMI or saline began 24 h after stereotaxic surgery. The results showed that DMI once a day during 9 days (10 mg/kg) reduced immobility in the forced swim test in the sham-lesion group (P<.02); however, in the dopaminergic lesion group submitted to DMI treatment, immobility remained at control level in agreement with other reports. DMI increased the firing rate of the LSN (P<.001) independently of the 6-OHDA lesion. In conclusion, the dopaminergic terminals of the NAcc seem to be essential for the motor manifestation associated with motivation induced by DMI in the forced swim test, given that the antiimmobility actions of DMI are blocked after a dopaminergic NAcc lesion; however, the effect on the firing rate of LSN neurons is still present.
-
the lowest effective dose of fluoxetine in the forced swim test significantly affects the firing rate of Lateral Septal Nucleus neurones in the rat
Journal of Psychopharmacology, 2001Co-Authors: Carlos M. Contreras, Juan Francisco Rodriguezlanda, Ana G Gutierrezgarcia, Blandina BernalmoralesAbstract:The administration of a relatively high dose of antidepressant drugs produces an increased neuronal firing rate of the Lateral Septal Nucleus (LSN) in the rat and a decreased immobility in rats forced to swim. However, it is unknown whether a minimally effective low-dose 21-day treatment with the selective serotonin reuptake inhibitor, fluoxetine, while reducing immobility in the forced swim test, also increases the neuronal firing rate of the LSN in Wistar rats. The total time of immobility decreased with a daily injection of 0.5, 1.0 or 2.0 mg/kg of fluoxetine (p< 0.001), and the lowest dose increasing the latency to the first immobility period (p < 0.0001) was 1.0 mg/kg. Therefore, the action of the 21-day fluoxetine treatment (1.0 mg/kg) on the firing rate of LSN neurones was tested in another group of rats. A total amount of 78 single-unit extracellular recordings was taken from the LSN of eight control rats (n = 40) and eight fluoxetine treated rats (n = 38). The LSN firing rate in the fluoxetine gr...
