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Results for “beta-Endorphin”

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PubMed1979

Behavioral activities of opioid peptides and morphine sulfate in golden hamsters and rats.

The behavioral effects of beta-endorphin, [D-Ala2, D-Leu5]-enkephalin and morphine were investigated in golden hamsters and in rats. In golden hamsters, beta-endorphin and [D-Ala2, D-Leu5]-enkephalin induced loss of righting reflex, whereas morphine caused no such effect. Both opiate peptides and morphine caused the inhibition of tail-flick response and catalepsy in rats. beta-Endorphin was the most potent, followed by [D-Ala2, D-Leu5]-enkephalin and then by morphine. The catalepsy induced in rats by [D-Ala2, D-Leu5]-enkephalin was different from that of beta-endorphin and morphine in that it produced catalepsy without muscular rigidity. beta-Endorphin and [D-Ala2, D-Leu5]-enkephalin caused hypothermia in golden hamsters; morphine was less active in altering the body temperature. beta-Endorphin caused hypothermia at high doses and hyperthermia at low doses in rats. These heterogenous behavioral responses indicate that multiple types of receptors mediate the effects of opiates in the central nervous system.

Animals↗
PubMed1977

In vitro pharmacology of the opioid peptides, enkephalins and endorphins.

In the guinea-pig ileum methionine-enkephalin, normorphine and morphine are equipotent in depressing electrically evoked contractions; leucine-enkephalin has about 25% of the activity. The mouse vas deferens is more sensitive to the enkephalins which are 30 to 60 times more potent than morphine. Fragments of beta-lipotropin61-91 (beta-endorphin) having sequences up to LPH76 are more potent in the mouse vas deferens than in the guinea-pig ileum but beta-endorphin is about equipotent in the two preparations. None of the peptides has antagonist activity. Methionine-enkephalin and normorphine are equipotent in inhibiting [3H]-naloxone binding by homogenate of guinea-pig brain in the absence of Na+ while leucine-enkephalin has only 25% of this activity. In the guinea-pig ileum, naloxone antagonises normorhine and the enkephalins equally well whereas in the mouse vas deferens about ten times more naloxone is required for the enkophalins that for normorphine. Methionine-enkephalin depresses output of acetylcholine in the guinea-pig ileum and of noradrenaline in the mouse vas deferens.

Animals↗
PubMed1976

Endorphins: profound behavioral effects in rats suggest new etiological factors in mental illness.

The endogenous morphinomimetic brain peptides Met5-enkephalin and alpha-, beta-, and gamma-endorphins have been evaluated in rats after intracerebrospinal fluid injection. beta-Endorphin produces marked, prolonged muscular rigidity and immobility similar to a catatonic state, counteracted by the opiate antagonist naloxone; this effect occurs at molar doses 1/100 to 1/400 that at which the other peptides or morphine block the response to painful stimuli. All peptides evoked dose-related, naloxone-reversible, wet-dog shakes in rats that had not been exposed to drugs. beta-Endorphin produced hypothermia, whereas gamma-endorphin produced hyperthermia. Such potent and divergent responses to naturally occurring subtances suggest that alterations in their homeostatic regulation could have etiological significance in mental illness.

Animals↗
PubMed1978

[Description of neurons immunoreactive to anti-beta-endorphin immune serum present in the infundibular nucleus in man].

Neurons containing peptide (s) immunologically related to beta-endorphin have been detected by immunochemistry in human adult and fetal hypothalami. Their perikarya are located in the infundibular nucleus. Some fibres terminate close to vessels in the median eminence, others form pericellular baskets around perikarya of non-immunoreactive neurons of the infundibular nucleus. These results suggest that the central nervous system elaborates beta-endorphin or immunologically related peptides.

Adult↗
PubMed1977

Negative naloxone effects in schizophrenic patients.

On the basis of the hypothesis that the opiate-like neuropeptides, such as beta-endorphin, may be involved in the etiology of schizophrenic symptoms, naloxone 1,2 mg and placebo were administered intravenously to 8 schizophrenic patients, using a double-blind, crossover design. Naloxone was not found to be different from placebo in effecting schizophrenic symptoms, including hallucinations and delusions.

Adult↗
PubMed1979

Sensitivity to enkephalin as a cause of non-insulin dependent diabetes.

Non-insulin-dependent diabetes is associated with facial flushing after alcohol in patients on chlorpropamide (chlorpropamide alcohol flushing, C.P.A.F.) especially when there is a family history of diabetes. C.P.A.F. in three subjects (two diabetics, one non-diabetic) was blocked by the specific opiate antagonist naloxone. In nine subjects (six diabetics) C.P.A.F. was reproduced by the enkephalin analogue with opiate-like activity [D-Ala2, MePhe4, Met (O)-ol] enkephalin (DAMME). C.P.A.F. thus may be due to increased sensitivity to endogenous opiates. DAMME and other substances with opiate-like activity, such as morphine and beta-endorphin, affect carbohydrate metabolism and insulin secretion. Increased sensitivity to endogenous opiates such as enkephalin may thus give rise to non-insulin-dependent diabetes associated with C.P.A.F.

Alcoholic Beverages↗
PubMed1979

Separation of opioid peptides utilizing high performance liquid chromatography.

Chromatographic procedures have been developed for resolving all of the known enkephalins and endorphins on a single column. The effect of eluant pH on the retention times and separation of the enkephalins and beta-endorphin was determined. By combining these separations with a sensitive radioreceptor assay it is possible to assay all of the opioid peptides in the pituitary gland or in various regions of the brain from individual small laboratory animals.

Amino Acid Sequence↗
PubMed1976

The C-fragment of beta-lipotropin: an endogenous neuroleptic or antipsychotogen?

Microinjection of the C-fragment (also called beta-endorphin), which is amino acid sequence 61-91 of the endogenous pituitary hormone, beta-lipotropin (beta-LPH), in the periaqueductal gray of the rat resulted in profound sedation and catalepsy, while microinjection of smaller fragments-that is, methionine-enkephalin [sequence beta-LPH-(61-65)] and its related pentapeptide, leucine enkephalin, and alpha-endorphin [sequence beta-LPH-(61-76)] resulted in attenuated forms of this behavior. This indicates that the C-fragment is an important neuromodulator of the central nervous system. The similarity of this behavior to that seen after systemic administration to experimental animals of exogenous neuroleptics suggests that a disturbance in the bioavailability of this neuropeptide to receptor sites in brain-perhaps due to lack of enzymatic cleavage from the circulating parent hormone, beta-lipotropin--may be an etiological factor in those psychopathological states for which the exogenous neuroleptics exert an ameliorative influence.

Analgesia↗
PubMed1979

Effects of neuropeptides on adenohypophyseal hormone response to acute stress in male rats.

The effects of bombesin and other unrelated oligopeptides on hormonal changes induced by stress were studied in conscious adult male rats. Restraint in the cold for 1 h increased plasma corticosterone and PRL levels and decreased GH values but had no effect on LH levels. Bombesin (5 microgram), given intracerebroventricularly (ivt) before stress, inhibited the PRL rise without affecting corticosterone, GH, or LH response. A complete blockade of PRL rise was observed with doses of bombesin ranging from 5 microgram to 100 ng ivt, regardless of the duration (15, 30, 45, or 60 min) or the nature (cold exposure or restraint at room temperature) of the stressor agents. Bombesin was 10(3) more potent as a PRL inhibitor when given ivt than when given iv, and its ivt effect was not reversed by naloxone (1 or 10 mg/kg). Among other unrelated peptides tested (beta-endorphin, neurotensin, substance P, and TRH; 5 microgram ivt), only neurotensin decreased plasma PRL levels in rats subjected to restraint in the cold for 1 h. These results show that in conscious male rats, centrally administered bombesin has a very potent and long acting inhibitory effect on PRL release induced by acute stress. Since a bombesin-like peptide has been found in rat brain, its physiological role in PRL regulation remains to be elucidated.

Animals↗
PubMed1979

ACTH release in pituitary cell cultures. Effect of neurogenic peptides and neurotransmitter substances on ACTH release induced by hypothalamic corticotropin releasing factor (CRF).

The effects of various neurogenic peptides and neurotransmitter substances on the release of ACTH induced by hypothalamic corticotropin releasing factor (HY-CRF) were investigated using monolayer cultured anterior pituitary cells. Test substances were given in combination with 0.05-0.1 hypothalamic extract (HE)/ml, because HE evoked a significant ACTH release and a linear dose response relationship was demonstrated sequentially between 0.0165 HE/ml and 0.5 HE/ml. Relative high doses of lysine-vasopressin showed a slight additive effect on the release of ACTH induced by 0.1 HE/ml. Leu-enkephalin, dopamine, prostaglandin E1 and E2 slightly reduced the release of ACTH induced by HY-CRF, but the inhibitory effect of these substances were not dose-related. Other tested substances including luteinizing hormone releasing hormone, thyrotropin releasing hormone, somatostatin, melanocyte stimulating hormone release inhibiting factor, beta-endorphin, neurotensin, substance P, vasoactive intestinal polypeptide, angiotensin II, norepinephrine, serotonin, acetylcholine, histamine and gamma-amino butyric acid showed neither agonistic nor antagonistic effect on the release of ACTH induced by HY-CRF. These results indicate that the release of ACTH is controlled specifically by HY-CRF and corticosterone, and modified slightly by some other substances such as vasopressin and prostaglandins, and that the effect of most other neurogenic peptides and neurotransmitter substances is negligible or non-physiological at the pituitary level.

Adrenocorticotropic Hormone↗
PubMed1979

[In vitro biosynthesis of beta-lipotropin in brain tissue].

We have recently developed methods to identify biosynthetized beta-endorphin and beta-lipotropin (beta-LPH) following incubation of Rat pars intermedia with radioactive amino acids. We used the same approach for rat brain tissue. In the striatum we found a peptide similar to beta-LPH while its identification in hypothalamus was less positive. This is the first demonstration of such biosynthesis and it could well be an important step in determining the biosynthetic patterns of cerebral endorphins and enkephalins.

Animals↗
PubMed1979

Specificity of cultured anterior pituitary cells in detecting corticotropin releasing factor(s): the effect of biologically active peptides and neurotransmitter substances on ACTH release in pituitary cell cultures.

Biologically active peptides and neurotransmitter substances were added to anterior pituitary cell cultures to examine the presence of corticotropin releasing factor (CRF)-like activity. Hypothalamic extract (HE) induced significant dose-related increase of ACTH, and the lowest effective dose was 0.01 HE/ml. Other tested substances including luteinizing hormone-releasing hormone, thyrotropin releasing hormone, melanocyte stimulating hormone release inhibiting factor, somatostatin, substance P, neurotensin, beta-endorphin. leu-enkephalin, met-enkephalin, bradykinin, norepinephrine, dopamine, serotonin, acetylcholine, histamine, gamma-amino butyric acid or gamma-hydroxy butyric acid showed no CRF-like activity. Relatively high doses of lysine vasopressin, arginine vasopressin and angiotensin II increased the release of ACTH in pituitary cell cultures, but the maximal ACTH response was markedly less than with HE. These results indicate that cultured anterior pituitary cells are sensitive and fairly specific in detecting CRF(s) comparing with other detecting procedures.

Adrenocorticotropic Hormone↗
PubMed2025

The inner dynamics of positive human-animal interactions: Investigating the roles of oxytocin, opioids, dopamine, serotonin and the proteome.

Research on the neuroendocrine basis of positive interactions has predominantly focused on oxytocin (OT), although dopamine (DA) and opioids also play crucial roles. Furthermore, these neurotransmitters are known to interact with each other but have seldom been studied concurrently. In this study, we quantified longitudinal changes in these neurotransmitters using a within-subject, 2 × 2 factorial design by varying human familiarity (familiar versus unfamiliar) and contact type (positive contacts versus ignoring) for 10 min human-pig interaction sessions. We obtained cerebrospinal fluid samples from 10 pigs through a spinal catheter 65 and 5 min before the test and at 10, 30, 60, 120 and 240 min after the start of the test. Samples at various timepoints were analysed for OT, DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), β-endorphin opioids concentrations, and using proteomics to explore novel protein candidates. Additionally, the duration and frequency of physical contacts initiated by the pig toward the human were coded from videos. The test condition (human familiarity × contact type) had a significant effect on the concentration of β-endorphin (F1118.59 = 4.45; P = 0.04) and 5-HIAA (F1,73.47 = 5.02; P = 0.03), and tended to affect the concentration of OT (F1, 119.8 = 3.19; P = 0.08) and DOPAC (F1,70.57 = 3.31; P = 0.07), but pairwise comparisons were not significant or showed complex changes. Specifically, OT was highest when the unfamiliar humans ignored the pig compared to when they delivered positive contacts (t70.6 = 3.31; P = 0.008), and β-endorphin tended to be higher after interacting with the familiar human compared to the unfamiliar humans (60 min post-test; t37.9 = 3.3; P = 0.055). There were only minor differences in the pigs' behaviour, suggesting that pigs seemed to perceive all test conditions as positive. Nevertheless, β-endorphin and OT appear to relate to different aspects of the interactions, possibly familiarity vs. novelty respectively.

Animals↗