Effects of Probiotic Supplementation on Exercise and the Underlying Mechanisms

Long-term, high-intensity exercise can trigger stress response pathways in multiple organs, including the heart and lungs, gastrointestinal tract, skeletal muscle, and neuroendocrine system, thus affecting their material and energy metabolism, immunity, oxidative stress, and endocrine function, and reducing exercise function. As a natural, safe, and convenient nutritional supplement, probiotics have been a hot research topic in the field of biomedical health in recent years. Numerous studies have shown that probiotic supplementation improves the health of the body through the gut-brain axis and the gut-muscle axis, and probiotic supplementation may also improve the stress response and motor function of the body. This paper reviews the progress of research on the role of probiotic supplementation in material and energy metabolism, intestinal barrier function, immunity, oxidative stress, neuroendocrine function, and the health status of the body, as well as the underlying mechanisms.

Reversion of beta 25-35-amyloid peptide-induced amnesia by NMDA receptor-associated glycine site agonists

The effects of D-cycloserine (DCS), a N-methyl-D-aspartate receptor-associated glycine site agonist, and milacemide (MIL), a glycine prodrug, were examined on learning impairments induced by administration of beta 25-35-amyloid peptide (3 nmol i.c.v.). Mice were examined for spontaneous alternation and step-down passive avoidance, 7 and 14 days after beta 25-35, respectively. The beta 25-35-induced deficits were reversed by DCS, 1-30 mg/kg i.p., or MIL, 3-100 mg/kg i.p., each drug being ineffective on control mice behaviours. These observations strengthen the therapeutic potential of glycine site agonists against the memory impairments induced by beta-amyloid peptides.

Excitotoxicity and neurological disorders: involvement of membrane phospholipids

Excitatory amino acids and their receptors play an important role in membrane phospholipid metabolism. Persistent stimulation of excitatory amino acid receptors by glutamate may be involved in neurodegenerative diseases and brain and spinal cord trauma. The molecular mechanism of neurodegeneration induced by excitatory amino acids is, however, not known. Excitotoxin-induced calcium entry causes the stimulation of phospholipases and lipases. These enzymes act on neural membrane phospholipids and their stimulation results in accumulation of free fatty acids, diacylglycerols, eicosanoids, and lipid peroxides in neurodegenerative diseases and brain and spinal cord trauma. Other enzymes, such as protein kinase C and calcium-dependent proteases, may also contribute to the neuronal injury. Excitotoxin-induced alterations in membrane phospholipid metabolism in neurodegenerative diseases and neural trauma can be studied in animal and cell culture models. These models can be used to study the molecular mechanisms of the neurodegenerative processes and to screen the efficacy of therapeutic drugs.

The effect of age on motor and cognitive deficits after traumatic brain injury in rats

Age is one of the most important predictors of outcome after human traumatic brain injury. This study used fluid percussion brain injury to investigate the effects of aging on outcome after brain injury in rats. Three-month-old (n = 8) and 20-month-old (n = 11) rats were injured at a low level (1.7-1.8 atm) of fluid percussion brain injury or received a sham injury (n = 6 for both age groups). Body weight and motor function (beam balance and beam walking) were assessed before injury and for the first 5 days after injury. Cognitive outcome was assessed with the Morris water maze on Days 11 to 15 after injury. Injury did not produce significant weight loss in either age group. At the low level of brain injury used in this study, the 3-month-old rats did not demonstrate any significant motor deficits on the beam-balance or beam-walking tasks. However, the 20-month-old rats displayed significant beam-balance deficits on each of the 5 postinjury test days and significant beam-walking deficits for the first 3 postinjury days. Although Morris water maze performance was impaired in both age groups, the magnitude of impairment was greater in the aged animals. These data demonstrate that traumatic brain injury in the aged animal is marked by increased motor and cognitive deficits, in the absence of pronounced compromise of the animal's general health.(ABSTRACT TRUNCATED AT 250 WORDS)

MK-801, a non-competitive NMDA receptor antagonist, produces facilitation of the micturition reflex in awake, freely-moving rats

MK-801 (dizocilpine), a non-competitive N-methyl-D-aspartate (NMDA) receptor blocker, produced a dose-dependent (30-120 micrograms/kg, i.v.) increase in the frequency of micturition (as well as the already described behavioral effects) in awake, freely-moving rats. The contraction amplitude was also slightly increased. In contrast, MK-801 administered to urethane-anesthetized rats resulted in complete inhibition of bladder contractions. The effect of MK-801 on the frequency of bladder contractions, therefore, is anesthetic dependent. Excitatory amino acids acting at NMDA receptors may play a role in the control of micturition.

The effect of age on outcome following traumatic brain injury in rats

Age of the patient is one of the most important predictors of outcome following human traumatic brain injury. This study employs the fluid-percussion model to investigate the effects of aging on outcome following traumatic brain injury in rats. The results revealed that there was an age-associated increase in mortality rate following both low (1.7 to 1.8 atm) and moderate (2.00 to 2.25 atm) levels of traumatic brain injury. Age-related changes in systemic physiological, neurological, and histopathological indexes of brain injury were also examined following a low level of traumatic brain injury. Traumatic brain injury produced equivalent acute hypertension and increased plasma glucose levels in both young adult and aging rats. Injury produced an acute increase in heart rate in the young adult rat group, while the heart rate decreased in the aged rats. At low levels of brain injury, no significant gross histopathological alterations were produced in either age group. Neurological outcome was assessed by measuring the duration of suppression of a number of nonpostural and postural reflexes and more complex somatomotor functions (righting, escape, head support). Except for head support, there was a significant age-related increase in the duration of the suppression of these reflexes following brain injury. These data demonstrate that aging is associated with an increased mortality rate and greater acute neurological deficits following traumatic brain injury. These data also demonstrate the usefulness of the fluid-percussion model for studying the mechanisms responsible for the age-related increase in vulnerability to brain injury.

Excitatory amino acid receptors, neural membrane phospholipid metabolism and neurological disorders

Excitatory amino acids and their receptors play an important role in membrane phospholipid metabolism. Persistent stimulation of excitatory amino acid receptors by glutamate may be involved in neurodegenerative diseases and brain and spinal cord trauma. The molecular mechanism of neurodegeneration induced by excitatory amino acids is, however, not known. Excitotoxin induced calcium entry causes the stimulation of phospholipases and lipases. These enzymes act on neural membrane phospholipids and their stimulation results in accumulation of free fatty acids, diacylglycerols, eicosanoids and lipid peroxides in neurodegenerative diseases and brain and spinal cord trauma. Other enzymes such as protein kinase C and calcium-dependent proteases may also contribute to the neuronal injury. Excitotoxin-induced alteration in membrane phospholipid metabolism in neurodegenerative diseases and neural trauma can be studied in animal and cell culture models. The models can be used to study the molecular mechanisms of the neurodegenerative processes and to screen the efficacy of therapeutic drugs for neurodegenerative disease and brain and spinal cord trauma.