PRL-8-53

PRL-8-53 is a synthetic supplement with potential benefits for short term memory. More evidence is needed for its effects, since all current evidence comes from a study funded by the patent holder.

This page features 4 unique references to scientific papers.

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Summary

All Essential Benefits/Effects/Facts & Information

PRL-8-53 is a synthetic Nootropic supplement, meaning it was created in a lab. Its full name is methyl 3-(2-(benzyl(methyl)amino)ethyl)benzoate.

Researchers found that oral supplementation of PRL-8-53 was able to improve avoidance learning in rats. One human study has also been done on PRL-8-53. Each participant ingested a placebo and PRL-8-53, at separate times, in a double blind crossover study. Participants then took a memory test, consisting of twelve monosyllabic words in a particular order. The test was conducted three times, immediately after supplementation, one day after supplementation, and four days after supplementation.

People that remembered more than eight words after taking a placebo experienced minor benefits, but people over 30 or with poor short term memory benefitted greatly from supplementation. In some cases, their score on the word test doubled.

No side effects were observed in the human study, and preliminary rodent evidence suggests PRL-8-53 is safe. Using PRL-8-53 as a dietary supplement, however, cannot be recommended at this time because it is a synthetic substance and all of the evidence for its effects comes from studies funded by the holder of the patent. Though this link should not invalidate the available evidence, independent replication would go a long way toward confirming PRL-8-53’s efficacy.

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How to Take

Recommended dosage, active amounts, other details

More evidence is needed to determine the ideal dosage for PRL-8-53. The effective dosage may vary, since the only human study on PRL-8-53 used a single dose of 5mg, while patent information on PRL-8-53 suggests a dosage range of 0.01-4mg/kg, with an 'ideal' range of 0.05-1.2mg/kg.

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Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects prl-8-53 has on your body, and how strong these effects are.

Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
Memory Notable - See study
The lone study noted mild increases in memory (14%) bordering on statistical significance in high performers on a word recollection test, with higher performances in subjects over the age of 30 regardless of initial performance (108-152% increase over placebo performance) and in poor performers (87.5-105%).
Working Memory Minor - See study
Memory acquisition appears to be mildly increased in the range of 18-31% in persons with poorer performance on a word recollection memory test, but is not improved in high performers.
Motor Control - - See study
Supplementation of 5mg PRL-8-53 has failed to improve hand motor control following supplementation.
Reaction Time - - See study
The dose of PRL-8-53 that improves memory formation does not appear to have any significant influence on reaction time.


1Sources and Structure

1.1. Sources

Methyl 3-(2-(benzyl(methyl)amino)ethyl)benzoate is a synthetic research chemical with the designation of PRL-8-53, created by the researcher Nikolaus R. Hansl[1] who is also the patent holder.[2] It is currently an unscheduled drug, which is a placeholder category for compounds not yet scheduled to be made illegal.

PRL-8-53 is a synthetic drug which is currently unscheduled.


2Neurology

2.1. Dopaminergic Neurotransmission

Apomorphine is a dopamine agonist, and causes compulsive gnawing in rats. Combining PRL-8-53 with apomorphine can be used to assess the dopaminergic effect of PRL-8-53 via change in gnawing behavior. PRL-8-53 at 4mg/kg increased apomorphine-induced gnawing in rats, and was also effective in improving conditioned avoidance learning, indicating that PRL-8-53 is a dopamine agonist.[1]

There is evidence in rats to suggest that PRL-8-53 is a dopaminergic agonist.

2.2. Other Mechanisms

PRL-8-53 has failed to enhance methamphetamine's actions in rodents (which is commonly seen with tricyclic antidepressants), which suggests that PRL-8-53 does not strongly enhance norepinephrine and serotonin activity; it also failed to inhibit monoamine oxidase (MAO) (receptor subset not specified) at concentrations up to 1mM in vitro in rats.[1]

PRL-8-53 has no known influence on MAO enzymes and does not augment methamphetamine.

2.3. Memory and Learning

Studies in rats have noted an increase in conditioned avoidance learning, with dose-dependent effects in the oral dosing range of 5-20mg/kg.[1]

Oral ingestion of a single dose of 5mg PRL-8-53 120-150 minutes prior to cognitive testing noted that after a word recollection test (twelve monosyllabic words orally given to participants) that recollection measured 24 hours and 96 hours after testing was increased with PRL-8-53 relative to placebo.[3] Overall improvements in recollection differed based on how many words were recalled under placebo, with the poor performers (six or less words) experiencing a 87.5-105% increase in recollection and the high performers (eight or more words) a 7.9-14% increase which failed to reach statistical significance; when controlling for subjects over the age of 30 only, a 108-152% increase was noted.[3]

Acquisition rates (immediately after the test) failed to improve overall with PRL-8-53 relative to placebo aside from the subgroup that remembered less than six words under placebo, where a mild 18% increase in acquisition was noted and a 31.4% increase when assessing only persons over the age of 30.[3]

The lone study in humans conducted by the patent holder has suggested relatively large increases in short term memory with single dose PRL-8-53. This information requires independent replication.


3Safety and Toxicology

3.1. General

According to patent information, the LD50 of PRL-8-53 in mice is 860mg/kg bodyweight and side-effects leading up to this dose include a reduction in motor activity[2] (also seen with high doses in the rat, which have an LD50 of 700-800mg/kg[1]). The estimated ED50 for reducing motor activity in the mouse is 160mg/kg[2] with minor reductions seen at 100mg/kg in the mouse but not rat[1] and the lone human trial failed to note any interactions with motor control at the 5mg dosage.[3] Injections of 150-200mg/kg in the mouse can induce convulsions, although lower doses do not.[1]

The lone human study using a single dose of 5mg PRL-8-53 has failed to note any significant or minor side-effects associated with supplementation.[3]

Based on very limited evidence, it seems that PRL-8-53 has a fairly large therapeutic threshold, but comprehensive toxicity studies in humans and rodents (looking at biochemical parameters) have not yet been undertaken.

Scientific Support & Reference Citations

References

  1. Hansl NR A novel spasmolytic and CNS active agent 3-(2-benzylmethylamino ethyl) benzoic acid methyl ester hydrochloride . Experientia. (1974)
  2. Process for hydrolyzing 3-trifluoromethyl phenethylamines
  3. Hansl NR, Mead BT PRL-8-53: enhanced learning and subsequent retention in humans as a result of low oral doses of new psychotropic agent . Psychopharmacology (Berl). (1978)
  4. Hansl NR, Mead BT PRL-8-53: enhanced learning and subsequent retention in humans as a result of low oral doses of new psychotropic agent . Psychopharmacology (Berl). (1978)

(Common misspellings for PRL-8-53 include PRL853)