Effects of a number of short peptides isolated from the brain of the hibernating ground squirrel on the eeg and behavior in rats

Abstract

Intracerebroventricular administration of the peptides kyotorphin (Tyr-Arg), neokyotorphin (Thr-Ser-Lys-Tyr-Arg), and Asp-Tyr at doses of 4 and 8 micrograms altered the behavior of rats in a manner similar to that seen after similar administration of brain fractions from hibernating ground squirrels (Citellus undulatus), which contained these peptides; there were increases in orientational reactions, increases in the frequency of stereotypical scratching movements, grooming, yawning, hiccuping, and sneezing. Animals became drowsy after 15-20 min. Peptides and brain fractions also had similar effects on the EEG of rats. Brain fractions reduced theta and alpha rhythms and enhanced delta and beta frequencies. Increases in delta waves were seen with all peptides (a 4-microgram dose of kyotorphin produced alternating increases and reductions in the delta rhythm). Inhibition of theta and alpha rhythms after administration of Asp-Tyr and kyotorphin was more transient than after brain fractions. Increases in beta frequencies were seen only after administration of 8 micrograms of Asp-Tyr, the smaller dose not producing this effect.

Neuropeptide Kyotorphin (Tyrosyl-Arginine) has Decreased Levels in the Cerebro-Spinal Fluid of Alzheimer’s Disease Patients: Potential Diagnostic and Pharmacological Implications

“…It was subsequently isolated from other sources, including the brains of mice and rats (Ueda et al, 1980), guinea pig, rabbits, and squirrels (Ignat’ev et al, 1998) and detected in the CSF in humans (Nishimura et al, 1991). Despite being about fourfold more analgesic than endogenous opioids (Shiomi et al, 1981a), KTP effect is only induced after direct injection in the brain.…”

Chemical Conjugation of the Neuropeptide Kyotorphin and Ibuprofen Enhances Brain Targeting and Analgesia

“…It acts as a neurotransmitter/neuromodulator in nociceptive responses in the central nervous system, having an analgesic potency approximately 4.2-fold higher than endogenous opioid peptides . Other activities have been proposed such as inhibiting cell proliferation and antihibernating regulation . The mechanism of action of this multifunctional peptide remains, however, unknown.…”

Evaluación in silico de péptidos bioactivos derivados de la digestión de proteínas presentes en la leche de bovino (B. taurus), oveja (O. aries), cabra (C. hircus) y búfalo (B. bubalis)

“…Los PBA inhibidores de CaMPDE (Fosfodiesterasa dependiente de Calmodulina) inhiben la respectiva enzima en vías de señalización intracelular [33]. Los PBA reguladores, particularmente el dipéptido con secuencia DY (ver Tabla 5), tienen una función reguladora de flujo iónico a través de sistemas de membranas [34]. En las clasificaciones de PBA con carácter anticancerígeno e inmunomodulador se encuentra únicamente un péptido, PGPIPN (ver Tabla 3), el cual ha sido aislado in vitro y se ha determinado su acción antitumoral e inmunomoduladora [35].…”