PubMed Health⌕ Search

Biomedical subjects

G A Olson

Publications and source records attributed to G A Olson.

15 recordsLinked to original sources
PubMed1979

Effects of influenza, mumps, and western equine encephalitis viruses on fetal rhesus monkeys (Macaca mulatta).

Pregnant Rhesus monkeys were infected via instillation of influenza, mumps and western equine encephalomyelitis viruses respectively into the amniotic sacs at approximately 90 days gestation to determine if fetal infections would occur. Virus was recovered from fetal tissues after seven days in 100% of the exposed animals. Thus, the viruses are capable of causing fetal infection. Rhesus monkey fetuses were inoculated with influenza, mumps and WEE viruses by the direct intracerebral route at approximately 90 days gestation to determine possible teratogenicity of the viruses. influenza virus caused no malformations or measurable fetal effects. Mumps virus resulted in significant fetal mortality. WEE virus resulted in a 100% incidence of encephalitis and hydrocephalus. Thus, mumps and WEE viruses are teratogens in primates and are potential teratogens of man.

Animals↗
PubMed1979

Effects of an enkephalin analog on complex learning in the rhesus monkey.

Facilitation of the learning of a discrimination reversal task for a reward of food was found in rhesus monkeys after subcutaneous administration of a potent pentafluorinated enkephalin analog. (D-Ala2)-F5-Phe4-enkephalin-NH2. General activity, short-term memory, startle, and analgesia, however, were not significantly affected. In a within-subject design, each of 6 monkeys (3 males and 3 females) received each of 5 doses of the enkephalin analog (0.1, 1, 10, 100, and 1,000 microgram/kg). One daily injection was made for 7 consecutive days, including pre- and posttests on the first and last days with the diluent control. The enkephalin doses, with the exception of the 0.1 microgram/kg level, produced significantly faster learning than the diluent. Some sex differences were suggested by the data, but these effects are difficult to interpret. The results suggest that relatively small amounts of this analog given systematically can exert a reliable effect on a complex behavior such as reversal learning at doses devoid of opiate effects, due perhaps to enhanced cognitive flexibility rather than improvement in short-term memory or association formation.

Analgesia↗
PubMed1979

Possible non-narcotic component to action of opiate peptides on tonic immobility.

Chickens were tested in a tonic immobility paradigm after a single intraperitoneal injection of either 0.0, 0.1, 1.0, 10.0; 100.0, or 1000.0 microgram/kg of the potent opiate analog, (D-Ala2, F5Phe4)-Met-enkephalin-NH2. An inverted-U relationship was obtained, with 100 microgram/kg being the most effective in prolonging immobility. This dose was used in subsequent studies involving pretreatment with naloxone or diluent followed by treatment with diluent, (D-Ala2, F5Phe4)-Met-enkephalin-NH2 (a strong opiate), or (D-Phe4)-Met-enkephalin (a weak opiate). The results indicated that although naloxone had mixed effects in attenuating the duration of tonic immobility, even the analog with negligible opiate activity reliably potentiated the response. Therefore, a component of the effect of opiate peptides on tonic immobility could be due to a non-narcotic action.

Animals↗
PubMed1979

Naloxone-induced suppression of food intake in normal and hypothalamic obese rats.

Intraperitoneal injections of naloxone hydrochloride (1, 2, 4, and 8 mg/kg) suppressed food intake in both normal and hypothalamic obese rats maintained on a 4-hr per day feeding schedule. The decrease in feeding was more pronounced in the animals with ventromedial hypothalamic lesions. Appetitively motivated feeding, i.e., the consumption of sweetened milk under nondeprived conditions, was also suppressed by naloxone, but there was no reliable difference between groups. It is concluded that opiate receptors located in the ventromedial hypothalamus are not essential for the effects of opiate agonists and antagonists on feeding behavior.

Animals↗
PubMed1979

Endogenous opiates: through 1978.

The discovery of receptors in the brain for opiates and the structure of the endogenous peptides for these receptors has led to an explosion of interest in this field. The present review is the first of an annual series. It summarizes many of the highlights of research with opiate peptides published with a date of 1978 or earlier.

Animals↗
PubMed1978

Dextran receptors as immunogens in caries prophylaxis.

1) Immunization of rats with dextran receptors appears to confer resistance to development of caries. 2) A significant negative correlation between antiserum titers and caries scores is observed in immunized rats. 3) Antiserum specific for dextran receptors does not inhibit in vitro adherence of live bacteria in sucrose supplemented media. 4) Free receptors can bind to dextran, thereby inhibiting its ability to induce bacterial agglutination.

Animals↗
PubMed1978

Neuropeptides and the blood-brain barrier in goldfish.

The general activity level of a goldfish is easily monitored by placing it in water to a depth of 2.5 cm in an aquarium on top of an activity meter. With this system, goldfish were administered a 5 microliter (80 microgram/kg) intracranial (IC) or intraperitoneal (IP) injection of one of 21 compounds and tested for general activity. The results indicated that activity decreased significantly over time and the peptides differentially decreased activity, with the greatest alterations in activity produced by two new enkephalin analogs: D-Ala2, F5Phe4-enkephalin-NH2 and Nalpha Nepsilon-bis-(D-Ala2-enkephalin)-Lys-NH2. Overall, decreased activity began approximately 3 min after an IC injections and 6 min after an IP injection. The longer latency after IP injections may indicate the time required for the substance, either in its original or fragmented form, to reach and cross the blood-brain barrier and makes a primary peripheral effect unlikely. Most of the peptides or possibly their metabolites appeared to enter the brain since no significant difference in activity existed after IC and IP injections, with both producing reliable decreases from the control. In summary, peptides can exert behavioral effects after both IC and IP administration in goldfish.

Animals↗
PubMed1978

Behavioral effects of D-Ala2-beta-endorphin in squirrel monkeys.

The effects of D-Ala2-beta-endorphin administered either intravenously (IV) or intracisternally (IC) in squirrel monkeys were tested using a number of behavioral measures: general activity, eating, social behavior, aggression/distress, analgesia, and startle/escape. There were 10 groups (N = 5) consisting of 4 dose levels administered IC (0.4, 40, 400 microgram/kg) and 6 dose levels injected IV (0, 4, 40, 80, 400, 800 microgram/kg). Every monkey was tested with all tasks on each of 5 identical repeated trials, one pre-injection baseline trial and 4 post-injection trials. After IC administration, the 2 largest doses exerted toxic effects, which were partially reversed with naloxone, producing in 2 cases muscular rigidity and profound sedation. The smaller 4 microgram/kg dose produced significant decreases in activity over trials but increased reactivity to noxious stimulation after the initial post-injection trial. With IV injection reliable changes in activity and approach to food were found. The results demonstrate significant behavioral effects of an endorphin analog in the squirrel monkeys after both central and peripheral injection.

Analgesia↗
PubMed1976

Inhibition of streptococcal adherence by human oral secretions and its possible relationship to dental caries.

Oral secretions were collected from 100 human volunteers, concentrated, and assayed for their ability to inhibit glucan-dependent adherence of S mutans strains to glass. Some samples were found to contain adherence inhibition activity. The inhibitor was heat labile and nondialyzable but dependent on the presence of a dialyzable molecule. Comparison of activities with the caries experience (DMFT) showed that individuals with the highest activity had significantly lower mean caries scores, but that cariesfree donors did not differ significantly from caries-positive donors in mean adherence inhibition activity. These results suggest that some persons may have substances in their oral secretions that play a role in resistance to dental caries.

Adolescent↗
PubMed1975

Technics for blood collection and intravascular infusion of reptiles.

Several methods for external sampling of blood and administration of intravascular fluids are applicable to reptilian species. This paper reviewed some of the technics that have been previously reported and introduced several new procedures applicable to snakes, turtles, alligators, crocodiles, and lizards.

Alligators and Crocodiles↗
PubMedDate not supplied

Endogenous opiates: 1990.

This paper, an examination of works published during 1990, is thirteenth in a series of our annual reviews of the research involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics this year include stress; tolerance and dependence, eating; drinking; gastrointestinal, renal, and hepatic functions; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; locomotor activity; sex, pregnancy, development, and aging; immunological responses; and other behavior.

Animals↗
PubMedDate not supplied

Endogenous opiates: 1991.

This paper is the fourteenth installment of our annual review of research concerning the opiate system. It includes papers published during 1991 involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal and renal 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↗