Novel opioid peptides
derived from casein (beta-casomorphins).
Rubiscolin-6, a delta opioid peptide
derived from spinach Rubisco, has anxiolytic effect via activating sigma-1 and dopamine D1 receptors.
This report is also in consistence with other in vivo evidences that endogenous opioid peptide
inhibit testosterone secretion27-32.
Identification of endogenous peptide ligands (6,7) that bind to their complementary receptors followed and they were termed, respectively, opioid peptides
and opioid receptors.
The idea behind this diet is that it reduces the amount of opioid peptides
(a kind of amino acid) in the blood.
The synchronous increase of neuropeptides and NK cells agrees with many studies in the area of neuroimmunomodulation research (16,17) and the finding that there is secretion of opioid peptides
The mechanism of action may involve a reduction of endogenous opioid peptide
actions that normally promote increases in dopamine release (Gonzales and Weiss 1998).
The availability of endogenous opioid peptides
, endorphins, enkephalins and dynorphins, led to the characterization of the opioid receptor subtypes, mu, delta, and kappa.
studies showing low pain thresholds (17) and abnormal beta-endorphin (an opioid peptide
neurotransmitter) (18) and methionine enkephalin (an opioid peptide
) (19) levels in PTSD patients.
Thus, it has been hypothesized that, in response to injury, opioid peptide
activity in regional sympathetic ganglia fails to increase, or tolerance develops to locally increased opioid activity, producing a hypersensitive or excessive response to autonomic activity (6, 9).
This is really the first evidence that the brain makes an opioid peptide
[of use] to the immune system," he says.
Endogenous opioid peptide
(EOP) decrease pain and studies have found that consumption of sweet ingesta increases endogenous opioid peptide
(EOP) activity in rat brain, plasma and cerebral spinal fluid, (12) and also human plasma.
During perinatal and prepubertal period, this opioid peptide
has paracrine modulating action on Sertoli cells proliferation and maintenance of testicular quiescence (GERENDAI et al.
The clinical trial report includes data from the four week observation period following one single administration of NP2, delivering Enkephalin, an opioid peptide
, specifically to nerves experiencing pain from cancer.
Additional evidence indicates that an alcohol-induced increase of opioid peptide
release affects alcohol consumption, and nonselective opioid antagonists that block all opioid receptors, such as naloxone and naltrexone, reliably decrease alcohol intake (Gianoulakis 2004; Oswald and Wand 2004).