Biomedical subjects

G A Olson

Publications and source records attributed to G A Olson.

At least 19 recordsLinked to original sources

PubMed1998

Endogenous opiates: 1997.

This paper is the twentieth installment of our annual review of research concerning the opiate system. It summarizes papers published during 1997 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; eating and drinking; alcohol; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurologic disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunologic responses; and other behaviors.

Animals↗

PubMed1997

Endogenous opiates: 1996.

This paper is the nineteenth installment of our annual review of research concerning the opiate system. It summarizes papers published during 1996 reporting the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress, tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.

Animals↗

PubMed1996

Endogenous opiates: 1995.

This article is the eighteenth installment of our annual review of research concerning the opiate system. It includes articles published during 1995 reporting the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects. The specific topics covered this year include stress: tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.

Affect↗

PubMed1995

Endogenous opiates: 1994.

This article is the 17th installment of our annual review of research concerning the opiate system. It includes papers published during 1994 involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics covered this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.

Animals↗

PubMed1994

The Tyr-MIF-1 family of peptides.

A review of research on the Tyr-MIF-1 family of peptides is presented with emphasis on Tyr-MIF-1 and its structure, passage through the blood-brain barrier, and both opiate antagonist and agonist properties. Family members MIF-1, Tyr-W-MIF-1 and Tyr-K-MIF-1 are also included.

Animals↗

PubMed1994

Endogenous opiates: 1993.

This paper is the sixteenth installment of our annual review of research concerning the opiate system. It is restricted to papers published during 1993 that concern the behavioral effects of the endogenous opiate peptides, and does not include papers dealing only with their analgesic properties. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; development; immunological responses; and other behaviors.

Affect↗

PubMed1993

Picrotoxin-induced seizures modified by morphine and opiate antagonists.

The effects of naloxone, Tyr-MIF-1, and MIF-1 on morphine-mediated changes in susceptibility to picrotoxin-induced seizures were studied. Rats were pretreated with naloxone, MIF-1, Tyr-MIF-1, or saline. At 15-min intervals, they received a second pretreatment of morphine or saline and then were tested for seizures following a convulsant dose of picrotoxin. Several parameters of specific categories of seizures were scored. Morphine increased the number of focal seizure episodes, duration of postseizure akinesis, and incidence of generalized clonic seizures. Naloxone tended to block the morphine-mediated changes in susceptibility. Tyr-MIF-1 had effects similar to naloxone on duration of postseizure immobility but tended to potentiate the effects of morphine on focal seizure episodes. The effects of morphine and the opiate antagonists on focal seizure episodes and postseizure duration suggest the general involvement of several types of opiate receptors in these picrotoxin-induced behaviors. However, the observation of antagonistic effects for Tyr-MIF-1 on immobility but agonistic effects for focal seizures suggests that the type of effect exerted by opiate agents may depend upon other neuronal variables.

Animals↗

PubMed1990

Lymphocytic leukemia and lymphosarcoma in a rabbit.

Lymphocytic leukemia and lymphosarcoma were diagnosed in a rabbit with lethargy, emaciation, and pallor. The diagnosis was made on the bases of results of hematologic analysis, cytologic evaluation of a bone marrow specimen, and histologic examination. The lymphosarcoma was identified to be of T-cell origin. Leukemia is rarely diagnosed in rabbits, although lymphosarcoma is fairly common in this species.

Animals↗

PubMed1989

MIF-1 is active in a chronic stress animal model of depression.

MIF-1 was tested in an animal model of depression that used unpredictable chronic stress. In this paradigm, rats received either no stressors or a daily protocol of a variety of stressors for 20 days, during which time daily, intraperitoneal injections of various compounds were given. The tricyclic antidepressant imipramine (5 mg/kg) and low doses (0.1 and 1.0 mg/kg) of MIF-1 significantly increased activity and decreased defecation in an open field on day 21. No dose of naloxone (0.01-10.0 mg/kg) acted as an antidepressant. A high dose (10.0 mg/kg) of MIF-1 significantly increased the effects of chronic stress and produced hyperalgesia. Chronically-stressed rats were significantly more analgesic than controls. The results indicate that MIF-1 can act as an antidepressant in this model.

Animals↗

PubMed1989

Differential effects of Tyr-MIF-1 and naloxone in two animal models involving benzodiazepine.

It has been shown previously that the endogenous brain peptide Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) can act as an antiopiate and can also increase binding and function at the GABAA/benzodiazepine receptor complex. We now describe the effects of this tetrapeptide in two models in which the antiopiate naloxone has been reported to decrease the activity of benzodiazepines. Unlike naloxone, Tyr-MIF-1 and MIF-1 neither prevented chlordiazepoxide-induced locomotor hyperactivity in mice on a tilting floor nor suppressed chlordiazepoxide-induced eating in rats. Thus, in these two systems, Try-MIF-1 did not act as an antiopiate or alter the effects of a benzodiazepine, indicating a selectivity in the actions of Tyr-MIF-1.

Animals↗

PubMed1989

An evaluation of distress following intraperitoneal immunization with Freund's adjuvant in mice.

Intraperitoneal immunization with Freund's adjuvant is frequently used to stimulate antibody production in mice. To evaluate the clinical and pathological effects of this technique, mice were immunized intraperitoneally with complete Freund's adjuvant and albumin, and the injection repeated 3-4 weeks later using incomplete Freund's adjuvant. This regimen induced a mean antibody titer against albumin of 1:280 within 7 days after booster immunization and increased the abdominal width, abdominal circumference and spleen weights of immunized animals. Food intake and body weight decreased after immunization, but returned to control levels within 1-2 weeks. Open-field activity was not affected. Neutrophilia, eosinophilia and monocytosis were present 7 days after immunization and persisted for the duration of the study. Gross and histopathological lesions included multiple granulomatous abdominal adhesions and lymphoid hyperplasia. Thus, intraperitoneal immunization with Freund's adjuvant and albumin produced some adverse effects in the animal (weight loss, neutrophilia and granulomatous peritonitis). However, the animals did not appear to be severely or chronically impaired, since food intake, body weight and locomotor activity were within normal limits for most of the post-immunization period.

Analysis of Variance↗

PubMed1988

Induction of arthritis in monkeys by immunization with type II collagen.

Immunization of two cynomolugus and three rhesus monkeys with purified type II collagen resulted in the development of polyarthritis. Arthritis first became clinically apparent 7 wk after primary immunization and persisted for 16 mo. Radiologic examination of the limbs demonstrated soft tissue swelling with severe joint destruction including loss of cartilage and bone. Involved joints eventually became ankylosed with permanent loss of some motion. All of the monkeys developed a response to the immunizing collagen as determined by ELISA of serum for antibodies. Arthritis was associated with weight loss and constitutional symptoms, including lethargy and refusal to eat. One monkey became so debilitated that it was necessary to euthanize it. Histologic examination of the joints showed synovial hypertrophy with pannus formation. A control monkey immunized with type I collagen suffered no apparent ill effects.

Animals↗

PubMed1986

Lesions in ventromedial hypothalamus or amygdala do not affect naloxone's suppression of water consumption.

Rats received lesions in the ventromedial hypothalamus (VMH) or amygdala, or were sham operated, and then were tested for two-hour intake of water after injections of naloxone (2 mg/kg), MIF-1 (2, 4, or 8 mg/kg), or diluent. There was a significant effect of test compound, with naloxone reducing consumption relative to the diluent control and the largest dose of MIF-1. Although MIF-1 tended to suppress drinking, the effect did not reach significance. There was no main effect for lesions, indicating that the amygdala and the VMH do not play a critical role in the effect of naloxone or MIF-1 on water consumption. A significant lesion by time interaction occurred, however, with amygdala-lesioned rats drinking the most in the first 30 min but much less after that. The VMH rats drank the most in the 30-60 min interval, but there were no differences in groups after 60 min. Thus, it appears that the intact VMH and basolateral amygdala are not necessary for naloxone's suppression of water consumption in the rat.

Amygdala↗

PubMed1985

Gastroduodenal ulceration in rabbits producing antibodies to prostaglandins.

The consistent occurrence of gastric and duodenal ulcers was observed in laboratory rabbits used for production of high-titer plasma antibody to 6-keto PGF1 alpha and PGE2. Perforations developed in 7 of 10 animals, usually just distal to the pyloroduodenal junction. The remaining rabbits showed gross and/or microscopic evidence of imperforate ulcers and erosions. These lesions appeared to be direct pathologic complications of an immune response directed against prostaglandins since animals immunized against met-enkephalin with similar methods had no ulcers.

6-Ketoprostaglandin F1 alpha↗

PubMed1985

Naloxone and fluid consumption in rats: dose-response relationships for 15 days.

Rats were given daily intraperitoneal injections of 10.0, 1.0, 0.1, 0.01, 0.001 or 0.0 mg/kg naloxone for 15 days. Each day after the injections, animals were allowed access to a 20% sucrose solution for two hours and to tap water for the subsequent 10 hours. Consumption of the sucrose solution by the group that received 1.0 mg/kg was reliably decreased on Day 1 and 2, reflecting the suppressive effect of naloxone at that dose. By Day 3 until the end of the experiment, however, the suppression was no longer significant, suggesting that tolerance had developed. A similar effect was seen with the group given the highest dose, 10.0 mg/kg; although drinking was significantly less than the control in each of the 15 sessions, this group showed a trend to increase intake over the days of the experiment, thus also indicating possible tolerance to the effect of naloxone. Drinking patterns of the other groups did not differ statistically from the control. Thus, the low doses had no ability to suppress consumption, and the lowest dose that did lower it soon lost that ability; the highest dose continued to suppress drinking throughout the study but with decreasing efficacy. High performance liquid chromatography (HPLC) demonstrated that the naloxone remained intact over the 15 days of the experiment, supporting the suggestion that tolerance to naloxone might have developed.

Animals↗

PubMed1984

MIF-1 (Pro-Leu-Gly-NH2) decreases activity in Siamese fighting fish (Betta splendens).

The effects of MIF-1 (Pro-Leu-Gly-NH2) on activity and aggression of male Siamese Fighting Fish ( Betta splendens) were considered. Animals were given intraperitoneal injections of 0.0 or 10.0 mg/kg MIF-1. After a 10-minute delay, they were placed in a 10 gallon aquarium and their activity was monitored for 60 minutes. Although aggressive responses in the presence of suitable opponents were not reliably affected, as significant decrease in general activity was produced. This is compatible with differential effects of MIF-1 across species.

Aggression↗

PubMed1983

Behavioral effects of melanocyte stimulating hormone release-inhibiting factor-1 (MIF-1).

Consideration of the isolation, structure, localization, and behavioral effects of melanocyte stimulating hormone release inhibiting factor (MIF-1) is followed by a review of its opiate antagonistic and clinical effects. Evidence pertaining to various hypotheses offered in explanation of these behavioral effects is examined and evaluated. It is concluded that MIF-1 affects behavior in many instances with possible antagonistic effects as well as clinical possibilities.

Animals↗

PubMed1982

Naloxone decreases consumption of liquid and solid sucrose in vagotomized rats.

Intraperitoneal injections of the opiate antagonist naloxone decreased food intake in both vagotomized and sham-vagotomized rats. Consumption of liquid and solid sucrose, which were used in order to equate baseline intake, was equally suppressed in both groups under food-deprivation and appetitively-motivated conditions at all doses of naloxone (1, 2, 4, and 8 mg/kg). It is concluded that, in contrast to previous findings, the vagus nerve does not mediate the suppressive effects of naloxone on feeding behavior.

Animals↗