Vinpocetine: Cognitive Enhancer's Role Expands to Incontinence and Epilepsy
The periwinkle has long been an established part of summer gardens. But research has revealed that this flower is more than just a pretty addition to landscaping. Studies have indicated that vinpocetine, a natural substance derived from vincamine, an extract of the periwinkle, may support cognitive health, alleviate some of the symptoms of urinary incontinence, and, when administered intravenously in animals, alleviate some of the negative effects that occur in epilepsy.
Early experiments with vinpocetine indicated it has five main mechanisms of action. It can selectively enhance brain circulation and the brain's use of oxygen without significantly altering circulation throughout the body. Vinpocetine also increases the brain's tolerance toward hypoxia (oxygen deficiency) and ischemia (obstructed blood flow) and acts as an anticonvulsant. In addition, it inhibits the enzyme phosphodiesterase (PDE)-1, which breaks down adenosine monophosphate, an important nucleotide that the body makes from the cellular energy molecule known as adenosine triphosphate (ATP). Finally, vinpocetine stops blood cells from sticking together. Later studies confirmed the above effects and pinpointed other mechanism of actions of vinpocetine (including its ability to act as a sodium channel blocker).
Many vinpocetine studies have focused on its potential ability to enhance brain function. Vinpocetine increases blood circulation and metabolism in the brain, which may be why vinpocetine reduced the loss of neurons due to decreased blood flow in animal studies.
In three studies of older adults with memory problems associated with poor brain circulation or dementia-related disease, vinpocetine-treated subjects experienced significantly more improvement than placebo-treated subjects on global cognitive tests reflecting attention, concentration, and memory.
In one study, the efficacy and tolerance of orally administered vinpocetine was investigated in patients suffering from mild to moderate organic psychological syndromes, including primary dementia. In the placebo-controlled, randomized, double-blind trial, 203 patients received daily for 16 weeks either 10 mgs of vinpocetine three times per day, 20 mgs of vinpocetine three times per day, or a placebo three times per day. On both the lower and higher doses, the patients treated with vinpocetine experienced statistically significant improvements in cognitive performance compared to the placebo groups. Vinpocetine was also superior to placebo in improving ratings of the "severity of illness." There were no clinically relevant side-effects reported and the frequencies of adverse events between patients treated with vinpocetine and placebo were comparable.
Although vinpocetine is best known for the part it plays in cognitive support, researchers also have unearthed another potential role for this substance—urinary incontinence. The standard drugs available for incontinence and low compliance bladder are limited by a low clinical efficacy and significant side effects. Previous in vitro studies indicated that the enzyme known as phosphodiesterase (PDE)-1 (which breaks down adenosine monophosphate) may be involved in the regulation of contractility in the bladder's layer of muscle. Due to this connection, researchers decided to investigate the effect of vinpocetine, a PDE-1 inhibitor, in people who did not respond to standard drug therapy and who had been told that surgery is needed to correct the problem.
The 19 subjects (10 women and nine men, average age 56) were given 5 mg per day of vinpocetine for two weeks, then 10 mg per day for another two weeks. In 11 subjects (57.9 percent) clinical symptoms and/or the holding and storage of urine were improved. In eight subjects, there was a marked improvement after vinpocetine treatment. In three of the subjects, there was a slight improvement after treatment. The other eight subjects did not respond to vinpocetine. Although the researchers called the initial data preliminary, they pointed out that this study represents the first evidence that a phosphodiesterase (PDE)-1 enzyme inhibitor such as vinpocetine "may be a novel approach to the treatment of lower urinary tract disorders."
Vinpocetine appears to be more effective in what's known as urge incontinence because it relaxes or desensitizes the bladder, whereas other agents that stimulate and strengthen the pelvic floor are more effective for stress incontinence. Urge incontinence is when an individual experiences involuntary passage of urine occurring soon after a strong sense of urgency to void. Stress incontinence is the inability to prevent escape of small amounts of urine during laughing, coughing, sneezing or lifting.
Vinpocetine also has been investigated for its potential role in epilepsy. One group of researchers induced convulsions in guinea pigs by using an agent called 4-aminopyridine (4-AP). The researchers injected the animals with vinpocetine and then observed its effects. Vinpocetine inhibited the undesirable electroencephalogram (EEG) changes induced by 4-AP. In addition, it prevented the hearing loss that usually accompanies 4-AP administration. The researchers concluded, "Vinpocetine could be a promising alternative for the treatment of epilepsy."
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