Nefiracetam
Encyclopedia
Nefiracetam is a nootropic
antidementia drug of the racetam
family.
Nefiracetam's cytoprotective actions are mediated by enhancement of GABAergic, cholinergic
, and monoaminergic neuronal systems that give antiamnesia effects to the Alzheimer's type and cerebrovascular type of dementia.
Nefiracetam has reduced testicular testosterone in both rats and dogs.
To investigate mechanisms of the testicular toxicity of nefiracetam and to find sensitive parameters to predict the toxicity, male beagle dogs were orally administered 180 or 300mg/kg per day of the drug once and for 1 and 4 weeks. Time-course changes in serum and/or testicular hormone levels and semen parameters, and testicular morphology were examined. The testicular testosterone level was decreased 4h after single administration of nefiracetam at 300mg/kg per day, but the progesterone level showed no change at that time. The serum testosterone level was decreased after single, 1-week or 2-week treatment. In contrast, the serum estradiol level was increased from 1- to 4-week treatment. No changes in serum LH, FSH and inhibin B levels were observed throughout the experimental period. Decreased sperm motility and increased number of malformed sperms were first observed in semen after 4-week treatment. Histopathological examination of the testis revealed moderate and severe seminiferous atrophy with multinucleated giant cell formation at 180 and 300mg/kg per day, respectively, after 4-week treatment, but not 1-week treatment. These results show that nefiracetam decreases testicular testosterone level in dogs following single oral administration of a high dose, and induces severe morphologic changes after 4-week treatment. This reduction is shown to be a sensitive parameter to detect the toxicity, and is suggested to be induced by the impaired conversion of progesterone to testosterone in Leydig cells of rats and dogs. Although the dosages used in the studies were 1500 mg/kg and 300 mg/kg, respectively.
Nootropic
Nootropics , also referred to as smart drugs, brain steroids, memory enhancers, cognitive enhancers, and intelligence enhancers, are drugs, supplements, nutraceuticals, and functional foods that improve mental functions such as cognition, memory, intelligence, motivation, attention, and concentration...
antidementia drug of the racetam
Racetam
Racetams are a class of nootropic drugs that share a pyrrolidone nucleus.-Mechanism:There is no generally accepted mechanism for racetams. They generally show no affinity for the most important receptors, although modulation of most important central neurotransmitters, including acetylcholine and...
family.
Nefiracetam's cytoprotective actions are mediated by enhancement of GABAergic, cholinergic
Cholinergic
The word choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation. Found in most animal tissues, choline is a primary component of the neurotransmitter acetylcholine and functions with inositol as a basic constituent of lecithin...
, and monoaminergic neuronal systems that give antiamnesia effects to the Alzheimer's type and cerebrovascular type of dementia.
Nefiracetam has reduced testicular testosterone in both rats and dogs.
To investigate mechanisms of the testicular toxicity of nefiracetam and to find sensitive parameters to predict the toxicity, male beagle dogs were orally administered 180 or 300mg/kg per day of the drug once and for 1 and 4 weeks. Time-course changes in serum and/or testicular hormone levels and semen parameters, and testicular morphology were examined. The testicular testosterone level was decreased 4h after single administration of nefiracetam at 300mg/kg per day, but the progesterone level showed no change at that time. The serum testosterone level was decreased after single, 1-week or 2-week treatment. In contrast, the serum estradiol level was increased from 1- to 4-week treatment. No changes in serum LH, FSH and inhibin B levels were observed throughout the experimental period. Decreased sperm motility and increased number of malformed sperms were first observed in semen after 4-week treatment. Histopathological examination of the testis revealed moderate and severe seminiferous atrophy with multinucleated giant cell formation at 180 and 300mg/kg per day, respectively, after 4-week treatment, but not 1-week treatment. These results show that nefiracetam decreases testicular testosterone level in dogs following single oral administration of a high dose, and induces severe morphologic changes after 4-week treatment. This reduction is shown to be a sensitive parameter to detect the toxicity, and is suggested to be induced by the impaired conversion of progesterone to testosterone in Leydig cells of rats and dogs. Although the dosages used in the studies were 1500 mg/kg and 300 mg/kg, respectively.