5. Mechanism involved in Aphrodisiacs
Drugs
These drugs act by enhancing the sex organ sensation
and performance. They improve the blood flow to the
male sex organs, thus improving the male libido. A
similar response in women may also produce an
increased sexual stimulation.
One of the mechanisms by which cyclic nucleotides
induce the relaxation of smooth muscle is through the
opening of potassium (K+) channels, which leads to the
efflux of K+ from the smooth muscle cell, down their
electrochemical gradient. This results in
hyperpolarization and an inhibitory effect on trans
membrane Ca2+ flux and eventually, smooth muscle
relaxation.
6. Another mechanism which causes penile erection is through
cyclic adenosine monophosphate pathway (cAMP). Corporal
smooth muscle relaxation is mediated via cAMP. The
activated membrane-bound adenylyl cyclase, which generates
cAMP, it activates protein kinase A and to a lesser extent,
protein kinase G. Prostagladin E1 also increases the
intracellular concentrations of cAMP in the corpus
cavernosum smooth muscle cells. The generation of cAMP
activates the Ca2+ pump and consequently, the level of free
cytoplasmic Ca2+ is reduced, resulting in smooth muscle
relaxation. Similarly, the protein kinase activates the cell-
membrane Ca2+ pump, leading to a decreased sarcoplasmic
Ca2+ concentration which induces a loss of contractile tone of
the penile smooth muscle and increase of blood flow in the
cavernous body resulting in erection.
7. Purposes of Aphrodisiacs Agents
To increase low libido.
To improve sexual performance.
In the treatment of impotence
To treat physiological problems that affect
sexual activity
8. Side Effects
arrhythmia of the heart
suicidal tendencies
mental disorders
tremors
headaches
fainting facial flushing
upset stomach
blurred vision
sensitivity to light usually occur with high doses.
9. Screening Methods of Aphrodisiac
Agents
A) Physical or behavioral methods ( In vivo Method)
i) Mating behavior test
ii) Libido test
iii) Potency test
iv) Orientation activity test
v) Sexual and vital organ weight test
B) Biochemical or Hormonal Methods ( In vitro Method)
i) Estimation of cholesterol level
ii) Estimation of sex hormones level
iii) Assay for nitric oxide synthase
iv) Assay for androgen receptor protein
10. Physical or behavioral methods
i) Mating behavior test
Healthy and sexually experienced male rats (200-300
gm) with brick sexual activity are divided into three
groups (n=6)
Group-I , receives distilled water(10ml/kg, p.o.)
Group-II, receives testing agent daily for 21 days
Group-III, receives standard drug i.e. sildenafil
(5mg/kg, p.o.) one hour prior to the experimentation
Than all the animals are exposed to dim light (1 w
fluorescent tube in a laboratory of 14’ x14’) at the
stipulated time of testing daily for 6 days prior the test
11. Female rates treated with ethinyl estradioal (100μg/animal p.o.) 48hrs and
with progesterone (1mg/animal, s.c.) 6hrs before pairing (1:1 ratio)
On 21st day , the experiment is conducted at 8pm and the male rats are
observed for-
Mounting frequency
Intromission frequency
Mounting latency
Intromission latency
Ejaculation latency
Post-ejaculation interval
Libido index
Compute above parameters of male sexual behavior and compare between
testing agent , control and standard drug.
12. ii) Libido test
Healthy and sexually experienced male rats (200-300
gm) with brick sexual activity are divided into three
groups (n=6)
Group-I , receives distilled water(10ml/kg, p.o.)
Group-II, receives testing agent daily for 21 days
Group-III, receives standard drug i.e. sildenafil
(5mg/kg, p.o.) one hour prior to the experimentation
Than all the animals are exposed to dim light (1 w
fluorescent tube in a laboratory of 14’ x14’) at the
stipulated time of testing daily for 6 days prior the test
13. The female rats should be made to receptive by
hormonal treatment
On the evening of 21st day the penis should be
exposed by retracting the sheath and applying
xylocaine 5 % ointment, 30,15 and 5 min before the
observation for mating frequency, intromission and
ejaculation .
Compare the data between testing agent , vehicle
control and standard drug treated groups.
14. iii) Potency test
Healthy and sexually experienced male rats (200-
300 gm) with brick sexual activity are divided into
three groups (n=6)
Group-I , receives distilled water(10ml/kg, p.o.)
Group-II, receives testing agent daily for 21 days
Group-III, receives standard drug i.e. sildenafil
(5mg/kg, p.o.) one hour prior to the
experimentation
15. On 21st day, the rat is placed on back with partial
restraint
The preputial sheath is pushed behind the glans by
thumb and index figure and rat is holded in this
manner for 15 min then the total penile relaxes is
recorded
Compare the data between testing agents, vehicle
and standard drug treated groups.
16. Biochemical or Hormonal Methods
a) Estimation of sex hormones level
Testing agent which produce significant reduction
of prolactin in males should enhance the levels of
luteinizing hormones, follicle stimulating hormones
and testosterone
The estimation of serum concentration of above
hormones leads to evaluation of aphrodisiac agents
17. ii) Assay for nitric oxide synthase
NO relaxes the smooth muscles of cavernosum
which leads to increase in flow of blood into male
sex organ
Therefore, estimation of NOs in male copulatory
organ and testes of treated and control groups help
to evaluate aphrodisiac activity of testing agents.
