Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats were made tolerant to morphine or to DALA, a synthetic analogue of met-enkephalin, by prolonged exposure to these compounds. Tolerance was assessed by evaluating the resistance of the treated rats to present catalepsy after an acute dose of the opiates. Both morphine and DALA induced tolerance and cross-tolerance to the cataleptic effect. Acute administration of morphine and DALA increased the concentration of DOPAC in striatum, limbic area and s.nigra of control rats. This increase was not present when morphine was given acutely to chronically morphine-treated rats, indicating that these animals were tolerant to this effect. Chronically morphine-treated rats given DALA presented partial tolerance to the biochemical effect of the peptide in limbic area and in s.nigra but not in striatum, indicating that only in certain areas was cross-tolerance produced by chronic morphine. When DALA was administered at different doses to chronically DALA treated rats, the peptide induced rise in DA catabolite was similar to that produced in control animals, so clearly there was no tolerance to this biochemical effect. In these animals cross tolerance to morphine's effect on DA metabolism was present in s.nigra but not in the other two areas, indicating that s.nigra is particularly sensitive to opiate-induced tolerance on DA metabolism.
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PMID:Similarities and differences between D-ALA2 MET5 enkephalin amide and morphine in the induction of tolerance to their effects on catalepsy and on dopamine metabolism in the rat brain. 689 40

1 Dermorphin and Hyp6-dermorphin are the first representatives of a new class of potent opioid peptides occurring in amphibian skin. They present the unique feature of having a D-Ala residue incorporated in the peptide molecule. 2 Dermorphin displayed a potent depressive action on electrically stimulated contractions of the guinea-pig ileum and mouse vas deferens preparations. Dermorphin was respectively 57,294, 18 and 39 times more potent than Met-enkephalin, Leu-enkephalin, beta-endorphin, and morphine on the guinea-pig ileum opiate receptors. On the vas deferens receptors, dermorphin was about as potent as the enkephalins and 40 times more potent than morphine. Naloxone was a powerful antagonist to dermorphin in both preparations. 3 Dermorphin produced potent and long-lasting analgesia in mice by intravenous injection, and in rats by intracerebroventricular injection, the ED50 being here of the order of 13-23 pmol/rat. Morphine was 752 and 2170 times less potent, depending on the analgesia test used. At high intracerebroventricular doses analgesia was accompanied by catalepsy. 4 Intracerebroventricular infusion of dermorphin induced development of tolerance and precipitation of withdrawal symptoms upon administration of naloxone. Both tolerance and physical dependence was consistently less marked with dermorphin than with morphine. 5 The minimum sequence requirement for full dermorphin activity was represented by the N-terminal tetrapeptide. The presence of the D-Ala2-residue was of crucial importance.
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PMID:Pharmacological data on dermorphins, a new class of potent opioid peptides from amphibian skin. 719 58

General pharmacological effects of the human corticotropin-releasing hormone, corticorelin (human) (CAS 86784-80-7), on the central nervous system, somatic nervous system, autonomic nervous system and smooth muscle, respiratory and circulatory system, digestive system and miscellaneous organs were investigated. 1. The central nervous system: Corticorelin (human) had little effect on hexobarbital-induced sleeping-time, maximal electroshock-induced convulsion, acetic acid-induced writhing, rota-rod performance. Corticorelin (human) at doses of more than 10 micrograms/kg i.v. induced flush of skin and pilo-erection, at doses of more than 30 micrograms/kg i.v. decreased body temperature, delayed expression of perphenazine-induced catalepsy and indicated hunched posture, and at the dose of 100 micrograms/kg i.v. induced the rise of awake-level and decrease of the total power of EEG, and decreased the spontaneous motor activity. 2. The somatic nervous system: Corticorelin (human) did not cause muscle relaxation in mice and had little effect on neuromuscular transmission in rats. No local anesthetic activity of corticorelin (human) was exhibited through inhibition of the corneal reflex in guinea pigs. 3. The autonomic nervous system and smooth muscle: Corticorelin (human) had no effect on the contraction of isolated ileum of guinea pigs induced by histamine and acetylcholine, and on the contraction of isolated trachea of guinea pigs induced by histamine, and the pupil diameter of rabbits. Corticorelin (human) at doses more than 30 micrograms/kg i.v. decreased spontaneous motility and contractile force of uterus of non-pregnant rabbits. 4. The respiratory and circulatory system: Corticorelin (human) had no effect on the contraction of isolated aorta of rats induced by norepinephrine. Corticorelin (human) at doses of more than 3 micrograms/kg i.v. decreased the blood pressure, increased heart rates and slightly increased the number of respiration in dogs. However, corticorelin (human) had no effect on ECG and femoral blood flow in dogs. 5. The digestive system: Corticorelin (human) at doses of more than 0.3 microgram/kg i.v. increased duodenal motility and contractile force, at doses of more than 1 microgram/kg i.v. increased colonic contractile force transiently and increased antral motility. Corticorelin (human) at doses of more than 3 micrograms/kg i.v. caused diarrhea and at doses of more than 30 micrograms/kg i.v. inhibited small intestinal propulsion in mice. Corticorelin (human) at dose of 100 micrograms/kg i.v. showed an inhibition of the gastric juice secretion and decreased the excretion of Na+, Cl- and H+ in rats. Corticorelin (human) produced slight gastric damages only at the highest dose of 100 micrograms/kg i.v.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:General pharmacological properties of the human corticotropin-releasing hormone corticorelin (human). 805 70

Using the latency for tail-flick after thermal stimulation we have assessed the effects of alpha-, gamma(1)- and gamma(2)-MSH on nociceptive threshold in the mice. Intracisternal injections of gamma(2)-MSH induced a distinct analgesia, while gamma(1)-MSH in the same doses gave only a minor analgesia. Intracisternal alpha-MSH instead gave a short-term hyperalgesia. The effect of gamma(2)-MSH was not blocked by any of the MC(4)/MC(3)receptor antagonist HS014, naloxone or by the prior intracisternal administrations of gamma(1)-MSH. However, the gamma(2)-MSH analgesic response was completely attenuated by treating animals with the GABA(A)antagonist bicuculline. The gamma(2)-MSH analgesic effect was moreover additive to the analgesia afforded by muscimol and ethanol, but not to that afforded by diazepam. In addition both gamma(1)- and gamma(2)-MSH induced moderate catalepsy, but could at the same time attenuate haloperidol induced catalepsia. We conclude that gamma(2)-MSH mediates a central analgesic effect via GABA-receptor dependent pathway that is distinct from melanocortic- and opioid-receptors. Moreover, the mechanism for gamma(2)-MSH's analgesic effect appears to be distinct from that causing moderate catalepsia by gamma-MSH's.
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PMID:The gamma(2)-MSH peptide mediates a central analgesic effect via a GABA-ergic mechanism that is independent from activation of melanocortin receptors. 1134 10


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