Enhancing the Function of Serotonin 5-HT1A Receptors


The inhibitory neurotransmitter, serotonin, activates the serotonin receptors, also known as 5-hydroxytryptamine receptors or 5-HT receptors.  Theses group or family of receptors are found in the central and peripheral nervous systems.  1 

A very functionally important 5-HT Receptor subtype is the 5-HT1A Receptor.  The 5-HT1A Receptor is the most abundant and widespread of all the 5-HT receptors.

The 5-HT1A Receptors are located in the central nervous system, specifically in the:

  • amygdala
  • cerebral cortex
  • hippocampus
  • raphe nucleus
  • septum

They also exists in lower densities in the:

  • basal ganglia
  • thalamus

When the 5-HT1A Receptors are activated, they can serve many biological functions in the human body.  These functions are listed in the Table below:

Functions of the 5-HT1A Receptors

Addiction 1
Blood Pressure5
Cardiovascular Function6
Heart Rate8
Penile Erection14
Pupil Dilation15
Sexual Behavior17

Other functional effects of 5-HT1A activation have been researched and can be found in the scientific literature:

  • Inhibition of drug-seeking behavior  2 
  • Facilitation of sex drive and arousal  3
  • Diminished food intake  4
  • Prolongation of REM sleep latency  5
  • Affect brain-derived neurotrophic factor (BDNF), which regulates mood and anxiety  6  7 

There are certain natural substances that may enhance the 5-HT1A Receptors.  They include:

Curcumin  8

Curcumin significantly prevented the stress-induced decrease in 5-HT(1A) mRNA and BDNF protein levels in the hippocampal subfields, two molecules involved in hippocampal neurogenesis. These results raise the possibility that increased cell proliferation and neuronal populations may be a mechanism by which curcumin treatment overcomes the stress-induced behavioral abnormalities and hippocampal neuronal damage. Moreover, curcumin treatment, via up-regulation of 5-HT(1A) receptors and BDNF, may reverse or protect hippocampal neurons from further damage in response to chronic stress, which may underlie the therapeutic actions of curcumin.

Ginger  9

In this study, bioactivity-guided fractionation of a ginger extract identified nine compounds that interact with the human serotonin 5-HT(1A) receptor with significant to moderate binding affinities (K(i)=3-20 microM).  In addition, the intestinal absorption of gingerols and shogaols was simulated and their interactions with P-glycoprotein were measured, suggesting a favourable pharmacokinetic profile for the 5-HT(1A) active compounds.

Ginko Biloba  10

Investigation of [3H]8-hydroxy-2(di-n-propylamino)tetralin binding to 5-HT1A receptors in cerebral cortex membranes of Wistar rats showed that the maximal number of binding sites (Bmax) was reduced significantly (22%) in aged (24-month-old) as compared with young (4-month-old) animals. Chronic treatment with Ginkgo biloba extract did not alter binding in young rats but increased binding density significantly (33%) in aged rats. These results confirm previously described age-related 5-hydroxytryptaminergic alterations.

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