Agmatine - a Magic Bullet in Clinical Neuroscience?

Today’s post is about Agmatine, a naturally occurring metabolite of the amino acid arginine, which is referred to in recent studies as both a “magic bullet” and a “magic shotgun”.

Normally when things sound too good to be true, you do need to be rather suspicious, but our reader Tyler has already been trialing Agmatine over the summer months and he continues to be a big believer.

As we will see in this post Agmatine has multiple different effects and while this is often the case with drugs and gives them both good and bad effects, in the case of Agmatine this ability to affect multiple targets is put forward as an advantage.

NAC, the antioxidant now widely used in autism, also has numerous beneficial effects and can even reverse propionic acid induced autism. I think we can call NAC a silver bullet.

You will recall that amino acids are the building blocks of proteins. Nine amino acids are called essential for humans because they cannot be produced by the human body and so must be taken in as food. Arginine is classified as a conditionally essential amino acid, depending on the developmental stage and health status of the individual. Preterm infants are unable to synthesize or create arginine internally, making the amino acid nutritionally essential for them.

Agmatine

Agmatine was discovered in 1910.  It is a chemical substance which is naturally created from the chemical arginine. Agmatine has been shown to exert modulatory action at multiple molecular targets, notably neurotransmitter systems, ion channels, nitric oxide (NO) synthesis and polyamine metabolism.

Many of agmatine’s effects are potentially relevant to neurological conditions like autism. My initial thought was that with so many different effects, how likely would it be that the overall effect would be positive?

• Neurotransmitter receptors and receptor ionophores. Nicotinic, imidazoline I1 and I2, α2-adrenergic, glutamate NMDAr, and serotonin 5-HT2A and 5HT-3 receptors.
• Ion channels. Including: ATP-sensitive K+ channels, voltage-gated Ca²⁺ channels, and acid-sensing ion channels (ASICs).
• Membrane transporters. Agmatine specific-selective uptake sites, organic cation transporters (mostly OCT2 subtype), extraneuronal monoamine transporters (ENT), polyamine transporters, and mitochondrial agmatine specific-selective transport system.
• Nitric oxide (NO) synthesis modulation. Differential inhibition by agmatine of all isoforms of NO synthase (NOS) is reported.
• Polyamine metabolism. Agmatine is a precursor for polyamine synthesis, competitive inhibitor of polyamine transport, inducer of spermidine/spermine acetyltransferase (SSAT), and inducer of antizyme.
• Protein ADP-ribosylation. Inhibition of protein arginine ADP-ribosylation.
• Matrix metalloproteases (MMPs). Indirect down-regulation of the enzymes MMP 2 and 9.
• Advanced glycation end product (AGE) formation. Direct blockade of AGEs formation.
• NADPH oxidase. Activation of the enzyme leading to H₂O₂ production.

Different effects are likely to predominate at different doses, as with many drugs.

Of the above effects many are implicated in autism.

Nicotinic, NMDA, and serotonin receptors are all deeply implicated in autism.

All the above ion channels including ASICs, which have not yet been covered in this blog, are implicated in autism. Acid Sensing Ion Channels (ASICs) are implicated in autism via the genetic research and surprisingly brain pH is disturbed in many neurological conditions. 

“Maintaining the physiological pH of interstitial fluid is crucial for normal cellular functions. In disease states, tissue acidosis is a common pathologic change causing abnormal activation of acid-sensing ion channels (ASICs), which according to cumulative evidence, significantly contributes to inflammation, mitochondrial dysfunction, and other pathologic mechanisms (i.e., pain, stroke, and psychiatric conditions). Thus, it has become increasingly clear that ASICs are critical in the progression of neurologic diseases.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4449961/

Nitric oxide is relevant to autism and any vasodilatory effect might be helpful to those with reduced cerebral blood flow. This benefit potentially goes beyond those with vascular dementia and may enhance memory and cognition in some.

It the effect on nitric oxide which body builders think gives them a benefit from taking Agmatine.

Polyamines and spermidine in particular are involved in autophagy, which is the intra-cellular garbage disposal service. When autophagy is impaired, as in many neurological conditions, this accumulating garbage gets in the way of cellular function. We already know that improving autophagy is one method of combating cognitive decline. We know that autophagy is impaired in autism.

NADPH oxidase and nNOS (Neuronal nitric oxide synthase) redox signaling cascades interact in the brain to affect both cognitive function and social behavior. I am not sure whether Agmatine will have a good or bad effect.                                                                  

The Research

I would be the first to point out that the Agmatine research is not like the high powered research we see from the scientists on this blog’s Dean’s List, but that does not mean the Agmatine may not be highly beneficial.  It is more like the copious research on antioxidants.

Agmatine: multifunctional arginine metabolite and magic bullet in clinical neuroscience? 

Agmatine, the decarboxylation product of arginine, was largely neglected as an important player in mammalian metabolism until the mid-1990s, when it was re-discovered as an endogenous ligand of imidazoline and α₂-adrenergic receptors. Since then, a wide variety of agmatine-mediated effects have been observed, and consequently agmatine has moved from a wallflower existence into the limelight of clinical neuroscience research. Despite this quantum jump in scientific interest, the understanding of the anabolism and catabolism of this amine is still vague. The purification and biochemical characterization of natural mammalian arginine decarboxylase and agmatinase still are open issues. Nevertheless, the agmatinergic system is currently one of the most promising candidates in order to pharmacologically interfere with some major diseases of the central nervous system, which are summarized in the present review. Particularly with respect to major depression, agmatine, its derivatives, and metabolizing enzymes show great promise for the development of an improved treatment of this common disease.                                                                                                                         

Agmatine: Clinical applications after 100 years in translation

Agmatine (decarboxylated arginine) has been known as a natural product for over 100 years, but its biosynthesis in humans was left unexplored owing to long-standing controversy. Only recently has the demonstration of agmatine biosynthesis in mammals revived research, indicating its exceptional modulatory action at multiple molecular targets, including neurotransmitter systems, nitric oxide (NO) synthesis and polyamine metabolism, thus providing bases for broad therapeutic applications. This timely review, a concerted effort by 16 independent research groups, draws attention to the substantial preclinical and initial clinical evidence, and highlights challenges and opportunities, for the use of agmatine in treating a spectrum of complex diseases with unmet therapeutic needs, including diabetes mellitus, neurotrauma and neurodegenerative diseases, opioid addiction, mood disorders, cognitive disorders and cancer.

“Agmatine is now considered to be capable of exerting modulatory actions simultaneously at multiple target sites, thus fitting the therapeutic profile of a ‘magic shotgun’ for complex disorders”

  

Mitochondrial protection 

Agmatine has been shown to exert direct protective effects on mitochondria at nanomolar concentrations. It has also been shown

to alleviate oxidative stress-induced mitochondrial swelling, possibly by acting as a free radical scavenger, and prevent Ca2+-dependent induction of mitochondrial permeability transition (MPT) by modulating itochondrial membrane potential and NF-kappaB activation and references therein). Importantly, these effects are implicated in apoptotic cell death. Therefore, mitochondrial protection is considered essential in contributing to the general cytoprotective effects of agmatine in various bodily systems and, thus, to its beneficial effects in a spectrum of disease models. Of special interest is a potential for agmatine utility in neurodegenerativediseases where mitochondrial malfunctions have been implicated (e.g., Parkinson’s disease).  

Drug development: therapeutic potential outweighing risks 

There remain constraints on progress towards practical development of agmatine as a drug. First, the lower level of protection against commercial competition afforded by ‘usage’ patents for new indications of known compounds, such as agmatine with its long known methods of chemical synthesis, is viewed as being much less lucrative by drug developers than that provided by ‘composition of matter’ patents for new chemical entities. Second, although research of new compounds to modulate endogenous agmatine metabolism holds promise, it is rudimentary and remains speculative. Third, even though agmatine, as a naturally occurring substance, has been developed and introduced to the dietary supplement and nutraceutical market, nutraceutical products in the USA fall under the ‘Dietary Supplement Health and Education Act (DSHEA)’, which forbids promotion of nutraceuticals for the treatment, cure, or prevention of any disease. Similar regulatory restrictions exist worldwide and severely limit the advertising of nutraceuticals to the medical market. 

Despite these constraints, compelling evidence indicates the therapeutic potential of agmatine for a spectrum of diseases. A summary of the advances made and the gaps still remaining for future research are indicated in Table 2. Although comparative efficacy studies with presently available drugs are still required, the broad safety profile of agmatine has been established with no serious adverse effects, either as a stand-alone or as an add-on treatment. This should be a paramount advantage when compared with most existing drugs and certainly to combination therapy.

Moreover, its general cytoprotective actions suggest that agmatine should be considered not only as a curative, but also as a preventive therapeutic.

Tyler’s Comments

Tyler’s comments in this blog regarding the use of Agmatine suggest that at different doses, the effect does indeed vary. At lower doses there can be negative effects like anxiety and aggression, but at 1.2 g (in a 50kg boy) the main affect is enhanced cognition.

https://epiphanyasd.blogspot.com/2017/06/modulating-wnt-signaling-in-autism-and.html?showComment=1498387748575#c1577296526823968689

https://epiphanyasd.blogspot.com/2017/08/music-for-autism-acquired-taste.html?showComment=1503773056629#c1943101059018652346

In treating strictly defined autism, cognitive function is often the most important target, unlike in milder forms of autism.

Tyler’s main purpose for trialing Agmatine was that it is thought to normalize the opioid system in the brain, via its action on adrenoreceptors.  Then came a mouse study in the valproic acid model of autism.

Agmatine rescues autistic behaviors in the valproic acid-induced animal model of autism

Autism spectrum disorder (ASD) is an immensely challenging developmental disorder characterized primarily by two core behavioral symptoms of social communication deficits and restricted/repetitive behaviors. Investigating the etiological process and identifying an appropriate therapeutic target remain as formidable challenges to overcome ASD due to numerous risk factors and complex symptoms associated with the disorder. Among the various mechanisms that contribute to ASD, the maintenance of excitation and inhibition balance emerged as a key factor to regulate proper functioning of neuronal circuitry. Interestingly, our previous study involving the valproic acid animal model of autism (VPA animal model) has demonstrated excitatory-inhibitory imbalance (E/I imbalance) due to enhanced differentiation of glutamatergic neurons and reduced GABAergic neurons. Here, we investigated the potential of agmatine, an endogenous NMDA receptor antagonist, as a novel therapeutic candidate in ameliorating ASD symptoms by modulating E/I imbalance using the VPA animal model. We observed that a single treatment of agmatine rescued the impaired social behaviors as well as hyperactive and repetitive behaviors in the VPA animal model. We also observed that agmatine treatment rescued the overly activated ERK1/2 signaling in the prefrontal cortex and hippocampus of VPA animal models, possibly, by modulating over-excitability due to enhanced excitatory neural circuit. Taken together, our results have provided experimental evidence suggesting a possible therapeutic role of agmatine in ameliorating ASD-like symptoms in the VPA animal model of ASD. 

in addition to a study in OCD:-

AGMATINE AMELIORATES SOCIAL ISOLATION INDUCED OBSESSIVE-COMPULSIVEBEHAVIOR IN MICE

Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by persistent intrusive thoughts (obsessions), repetitive ritualistic behaviors (compulsions) and excessive anxiety. Obsessive-compulsive disorder is classified as an anxiety disorder under DSM-IV-TR guidelines. In OCD, the levels of serotonin and nitric oxide decreased; whereas levels of dopamine and glutamate increased in brain. Environmental conditions such as isolation from social surroundings lead to anxiety and increased level of aggression. The present study was designed to examine the effect of agmatine in social isolation induced obsessive-compulsive behavior on marble burying behavior and locomotor activity. Agmatine (20, 40 and 80 mg/kg, i.p.) was administered in different groups of mice; activity was observed 30 min after dosing. Acute treatment of agmatine (40 and 80 mg/kg, i.p.) significantly reduced marble burying behavior. Moreover, hyperlocomotion was observed in socially isolated animals and agmatine was found to attenuate the same without affecting basal locomotions. In conclusion, agmatine effectively decreases social isolation induced obsessive-compulsive behavior in mice

I think it is fair to say that we do not know which mode(s) of action are in effect at this dosage. Clearly dosage is very important.

Given the importance of maximizing cognitive function in those with some cognitive dysfunction, Agmatine is clearly well worthy of further investigation.

Conclusion

Agmatine does indeed seem to have to potential to benefit some people with neurological disorders.  Is it a magic bullet for everyone? I doubt it, but that is an unrealistic expectation for any drug.

If it can improve cognition, even in a minority of autism, that would be a significant finding. Hopefully other readers of this blog will have the same positive experience as Tyler.  It will be interesting to find out how the effective dose varies. Depending on which brand you use, 1 teaspoon (5ml) of agmatine powder contains between 2.2 and 3.5 grams, which looks odd.  Probably best to weigh it to be sure.

Agmatine sulphate/sulfate is widely available in North America as a body builder’s supplement, but is banned in Europe. It was not banned for safety reasons, rather some odd EU rule that since it was not sold before 1997, it now needs to go through an approval process, that someone would have to pay for, before it can continue to be sold. Agmatine is not such an effective body building supplement to warrant anyone investing much in it. Hopefully the FDA will not ban it in the US.