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Biomedical subjects

R D Olson

Publications and source records attributed to R D Olson.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1982

Effects of MIF-I, sex, and weight on tonic immobility in lizards (Anolis carolinensis).

Three experiments were done with the lizard, Anolis carolinensis, as a follow-up on our previous work which showed that MIF-I reduced tonic immobility (TI) during the breeding season and that females had longer TI durations than males in the non-breeding season. In June, during the breeding season, 60 male and 60 female lizards were injected with 0.1 mg/kg of MIF-I or naloxone or the diluent vehicle and placed in small aquaria for ten minutes. TI was then induced in the small aquaria. Similar experiments were conducted in September and October (non-breeding season). There was a reduction in TI durations in MIF-I and naloxone-treated lizards of both sexes in June, but the differences between drug treatment groups and controls were not significant. In September and October, MIF-I treatment resulted in TI durations similar to controls but naloxone treatment resulted in slightly shorter durations. Increased TI duration in females as compared to males was seen during both seasons, but diminished during the breeding season. Weight was found to be a factor in male lizards, with males greater than or equal to 4.0 g showing significantly longer TI durations. The lack of a significant effect of MIF-I on TI durations during the breeding season is possibly due to changes in the experimental design from the earlier report.

Animals↗
PubMed1982

Effects of naloxone and its quaternary form on fluid consumption in rats.

Three studies were performed on albino rats to determine the effects of naloxone and its quaternary derivative, naloxone methylbromide, on fluid consumption. The doses of the quaternary naloxone were equated with naloxone by molarity and effectiveness in order to facilitate direct comparisons. All rats were deprived of food and water for 12 hr and exposed to a 20% sucrose solution for a 2 hr period. In Experiment 1, a low (0.01 mg/kg) dose of naloxone or an equated dose of quaternary naloxone was given ICV and immediate access allowed to the fluid on four consecutive days. Animals receiving naloxone were not significantly different from controls, and rats receiving quaternary naloxone exhibited seizures, resulting in decreased consumption. In Experiment 2, the low dose of naloxone or the equated dose of quaternary naloxone was given IP for four consecutive days and neither was significantly different from controls. In Experiment 3, animals were given an IP dose of either 1 mg/kg naloxone, a 1 mg/kg or 50 mg/kg dose of quaternary naloxone, or saline and tested for a single 2 hr period. The doses of 1 mg/kg naloxone and 50 mg/kg quaternary naloxone produced significantly less drinking than controls. In all studies, the initial 30 min period produced the most drinking. Suppression of drinking by a dose of 50 mg/kg quaternary naloxone suggested, in contrast to other studies, that it may cross the blood-brain barrier at high doses.

Animals↗
PubMed1982

Failure of MIF-1 or naloxone to reverse ischemic-induced neurologic deficits in gerbils.

MIF-1 and naloxone exert similar actions in several situations. Since naloxone, at a dose of 1 mg/kg IP, has been reported to reverse the neurologic deficits of gerbils whose right common carotid artery had been occluded, MIF-1 was tested under the same conditions and the effects compared with naloxone. Doses of 0.1, 1.0, and 10.0 mg/kg IP of MIF-1 and naloxone did not significantly alter the signs of either moderate or severe neurologic deficits. Thus, the results of this study with gerbils do not add evidence for the use of these opiate antagonists in strokes.

Animals↗
PubMed1982

Functional and metabolic preservation of the immature myocardium with verapamil following global ischemia.

This study investigated the effects of the calcium antagonist verapamil on the functional and biochemical recovery of the immature heart following 30 minutes of normothermic ischemia. Verapamil (0.2 mg per kilogram of body weight) was infused into the aortic root in 5 puppies (8 to 10 weeks of age) prior to cardiopulmonary bypass. Five additional puppies received saline solution as a control. Left ventricular developed pressure, rate of rise of left ventricular pressure (dP/dt), left ventricular endsystolic pressure-diameter relationship (emax), compliance, and water content were assessed before and after bypass. Serial myocardial biopsies for adenosine triphosphate (ATP) and creatine phosphate were obtained. Puppies pretreated with verapamil recovered more than 80% of the preischemic left ventricular developed pressure, dP/dt, and emax in contrast to 50% recovery in the controls (p less than 0.05). The ATP content declined 40% during the interval of ischemia in the control puppies, versus 14.6% in the verapamil-treated puppies (p less than 0.05). Myocardial compliance was preserved in the verapamil-treated puppies and was associated with significantly less myocardial water content (78% versus 80.1% in the controls)(p less than 0.01). This study demonstrates the protective effects of verapamil on the immature heart during ischemic arrest. These results suggest that verapamil may be a useful adjunct to current methods of protecting the infant heart during cardiopulmonary bypass.

Adenosine Triphosphate↗
PubMed1982

Survey of reproductive events of wives of employees exposed to chlorinated dioxins.

To determine whether paternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or other polychlorinated dioxins might be associated with adverse pregnancy outcomes, an interviewer-administered questionnaire survey was conducted among wives of Dow Michigan Division employees in the Midland, Michigan, area who had been potentially exposed to dioxins. A control group consisted of wives of employees who had no dioxins exposure and whose hire dates were comparable to those of the men in the exposed group. A total of 737 conceptions, which resulted in 637 live births and 10 stillbirths and spontaneous abortions, were identified as having paternal exposure; 2031 conceptions, resulting in 1785 live births and 246 stillbirths and spontaneous abortions, were identified as having no paternal exposure to any isomer of dioxin. Odds ratios were calculated for dependent variables consisting of spontaneous abortions, stillbirths, infant deaths and several categories of congenital malformations. Trend analysis was performed for duration-of-paternal-exposure of 12 months or less, or more than 12 months. Overall, no statistically significant associations were found between any exposure and pregnancy outcome, either before or after stratification by pertinent sets of up to nine covariables.

Abnormalities, Drug-Induced↗
PubMed1982

Beta adrenergically mediated release of renin in the dog is not confined to either beta-1 or beta-2 adrenoceptors.

The role of the renal beta-1 and beta-2 adrenoceptor subtypes in renin release was evaluated in anesthetized dogs. The renal baroreceptor and macula densa mechanisms of renin release were inhibited by pretreatment with indomethacin (8 mg/kg i.v.). Thus, the beta adrenergic mechanism of renin release was functionally isolated. Intrarenal infusion of isoproterenol at two infusion rates elicited local renal effects and systemic effects at the low and high infusion rates, respectively. Renin secretion was stimulated at both infusion rates. Isoproterenol elicited a significant renin release in the presence of beta-1 adrenoceptor blockade with atenolol and in the presence of selective beta-2 adrenoceptor blockade with IPS-339. In addition, intrarenal infusion of albuterol, a selective beta-2 adrenoceptor agonist, stimulated renin release in the absence and presence of atenolol. These results lead to the conclusion that beta adrenergically mediated release of renin in the dog is not confined to either the beta-1 or beta-2 adrenoceptor subtypes.

Adrenergic beta-Antagonists↗
PubMed1981

Tonic immobility produces hyperalgesia and antagonizes morphine analgesia.

Hyperalgesia was demonstrated during and immediately after termination of tonic immobility in the lizard Anolis carolinensis. Additionally, tonic immobility antagonized morphine-induced analgesia. In conjunction with other research, these data suggest that the response is accompanied by a reduced availability of serotonin, possibly at postsynaptic receptors of raphe neurons.

Analgesia↗
PubMed1981

Differential effects of neuropeptides on short-term memory in primates.

In a within-subject design, six rhesus monkeys (3 males and 3 females) received a 100 micrograms/kg injection of one of seven neuropeptides or a diluent control solution and were then tested for activity level, learning (discrimination reversal), short-term memory (delayed response), and for responsiveness to noxious stimuli. One daily injection was made with a different peptide for 10 consecutive days, including pre- and post tests on th first and last days with the diluent control. DSIP and D-Phe4-Met enkephalin seemed to produce some interference with short-term memory, while alpha-MSH showed some facilitation of it, as indicated by interactions of the peptides with the delay periods of 0, 15, or 30 sec. Sex differences were found in the learning task and the responsiveness to a noxious stimulus, suggesting the possibility of interactions between the peptides and endogenous hormones.

Animals↗
PubMed1981

Effects of MIF-I and sex differences on tonic immobility duration in the lizard, Anolis carolinensis.

In June, 36 lizards (males and females) were injected with 0.01, 0.1, 1.0, 10.0, or 100 mg/kg of MIF-I, or the diluent vehicle, and placed in a cage for ten minutes. Tonic immobility (TI) was then induced on an open lab table. All doses of MIF-I significantly reduced TI duration as compared to the duration with the diluent alone. In subsequent experiments lizards were injected with 0.1 mg/kg of MIF-I, 0.1 mg/kg of naloxone, or the diluent vehicle, and placed in small aquaria for ten minutes. TI was then induced in the small aquaria. In July, using 60 females, MIF-I and naloxone slightly reduced the duration of TI, but not significantly, and overall TI durations were reduced as compared with the first experiment possibly because the lizards could escape from the view of the experimenter in the corners of the aquaria. A third experiment was done in late September and early October with 120 males and 120 females. No drug effect was seen, but there was a significant difference between the TI durations of males and females, the females having longer durations. A relationship between the difference in response to MIF-I and the breeding seasons of the lizards could not be determined due to the possibility that the change in experimental design after the June experiments may alone have accounted for the loss of the significant response to MIF-I.

Animals↗
PubMed1981

Endogenous opiates: 1980.

Vast amounts of research have been done that have attempted to delineate the pharmacological and physiological effects of the endogenous opiate peptides. A great deal of knowledge has also been accumulated in a limited time span concerning the types and locations of the opiate receptors and peptides, as well as their functions. In 1980, reports were made concerning the effects of these peptides on analgesia, on tolerance and dependence, on activity, on learning and memory, on schizophrenia and other types of emotional disturbances, and on physiological responses such as eating and drinking, cardiovascular responses, and sexual function. Additional understanding was also gained concerning their interactions with neurotransmitters, other neuropeptides, and hormones. These and other studies published only in 1980 are reviewed in this paper, which is the third of an annual series.

Animals↗
PubMed1981

Alpha adrenergic-mediated renin release is prostaglandin-dependent.

The contribution of the alpha adrenergic receptor activation to the sympathetic mediated renin release was examined by utilizing intrarenal phenylephrine infusion in beta adrenergically blocked anesthetized mongrel dogs. Increasing doses of intrarenal phenylephrine resulted in a dose-dependent decrease in renal blood flow, a dose-dependent decrease in urinary excretion of sodium and a stimulation of renal renin release which was not dose-dependent. The effect of intrarenal phenylephrine on renin release was totally abolished by pretreating the dogs with indomethacin, even though neither the vasoconstriction nor the decrement in urinary sodium excretion was altered by the drug. In addition, intrarenal phenylephrine did not elicit renal renin release in dogs with kidneys that were rendered nonfiltering. These data are consistent with the hypothesis that exogenous renal alpha adrenergic stimulation in the dog contributes to renin release through the prostaglandin system and that the stimulation of the macula densa mechanism is responsible for the major effect of phenylephrine on renin release.

Animals↗
PubMed1980

Effects of Pavlovian conditioning and MIF-I on the development of morphine tolerance in rats.

Thirty male Sprague-Dawley-derived rats were given daily IP injections of morphine (5.0 mg/kg) in the presence of a specific set of environmental cues for eleven consecutive days. Twelve hours after each morphine session, a control injection was given in a different environment. On Day 12 through 14 the environmental cues associated with each session were reversed. On Day 15 environmental cues associated with each session were the same as on Days 1-11. Analgesia was assessed by the tail-flick method 30 minutes after each morphine and control injection. Four independent groups (n=6) received either a lower (0.1 mg/kg) or a higher (5.0 mg/kg) dose of MIF-I either 10 minutes before or immediately after each morphine and control session. A control group received an injection of a diluent vehicle both before and after each session. None of these peptide-treatments significantly affected either acute action of morphine or the development of tolerance across days. Tail-flick latencies from both morphine and control sessions significantly decreased across days. On Day 12, when morphine was administered in the presence of cues not previously associated with its administration, tail-flick latencies were significantly longer than on the previous day. Tail-flick latencies did not change from Day 11 to Day 15 during control sessions. Morphine-session latencies did not change from Day 14 to Day 15, although they did decrease from Day 12 to Day 14. The significant morphine-induced analgesia on Day 15 of the experiment increases a remarkable resistance to the development of tolerance to morphine. The results partially support the hypothesis proposed by Siegel [115-18] that principles of Pavlovian conditioning exert an important influence on the development of tolerance to morphine.

Animals↗