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Biomedical subjects

N Smith

Publications and source records attributed to N Smith.

At least 235 records · Page 13Linked to original sources
PubMed1977

Reclaimation.

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Australia↗
PubMed1976

Reduction of morphine-withdrawal aggression by conditional social stimuli.

Sixty male hooded rats were made physically dependent on morphine by steadily increasing doses of morphine sulphate. A maintenance dose of 400 mg/kg/day was reached in 10 days and was continued for 5 additional days. At the end of the 15-day period all rats were withdrawn for 72 h and aggressive responses (attacks, rearing, and vocalization) were recorded for a 60-min period. One treatment group, in which a social experience had been paired with each morphine injection, showed significantly less morphine-withdrawal aggression than rats in two other groups which either remained socially isolated throughout the addiction period, or were grouped both at the time of morphine injection and during between-injection intervals.

Aggression↗
PubMed1976

Secondary reinforcement property of a stimulus paired with morphine administration in the rat.

Rats learned to run to the correct arm of a Y-maze. Correct responses were reinforced with morphine injection paired with a conditional tone stimulus. After the maze response was well established, extinction trials were run. During extinction half of the animals received neither morphine nor tone as a consequence of a correct response, while the other half received the tone but no morphine. Rats receiving the tone during extinction required significantly more trials to reach the extinction criteria than rats not receiving tone presentations. Extinction with the tone also facilitated relearning of the maze response. The results support the view that morphone is a potent reinforcer, and that stimuli paired with morphine administration acquire the properties of a secondary reinforcer.

Acoustic Stimulation↗
PubMed1976

Biliary secretion in elasmobranchs. I. Bile collection and composition.

Bile composition and secretion were studied in tow elasmobranch species, Squalus acanthias (spiny dogfish shark) and Raja erinacea (small skate), after ligation of the common duct and insertion of cannulas into the gallbladder lumen. Fish were then allowed to swim freely in large pools and bile was collected in balloons attached to the externalized cannulas. Both species secreted bile for periods of 4-7 days at a maximum rate of 1.77 +/- .89 ml/kg per 24 h in Squalus acanthias and 2.66 +/- .89 ml/kg per 24 h in Raja erinacea. Comparison of the composition of cannula and gallbladder bile indicated that hepatic bile could be collected by this technique in both species without effective contact with gallbladder epithelium. The low concentrations of HCO3- and CL- and the gigh bile salt levels in dogfish gallbladder bile indicate that mechanisms for concentration and acidification of bile in the gallbladder developed early in vertebrate evolution. These results indicate that gallbladder cannulation in free-swimming elasmobranchs is a useful technique for the study of bile secretory and excretory function in marine species.

Animals↗
PubMed1976

Biliary secretion in elasmobranchs. II. Hepatic uptake and biliary excretion of organic anions.

[35S]Bromosulfophthalein ([35C]BSP), [14C]sodium taurocholate ([14C]NaTC), AND 10 MG OF UNLABELED BSP.and of phenol-3,6-dibromophthalein disulfonate (DBSP) per kilogram body weight were injected in the caudal artery of free-swimming dogfish sharks (Squalus acanthias) and small skates (Raja erinacea). Twenty-four hours later, 85.8 +/- 15.7% of [35S]BSP was recovered in bile and liver in dogfish and 78.4 +/- 9.9% in skates. Similar results were obtained for [14C]NaTC. Unlabeled BSP or DBSP (10 mg/kg body wt) were also selectively excreted in bile over a 4-day period and at comparable rates in both species. More than 85% of [35S]BSP, BSP, and DBSP in bile was in unconjugated form. Selective hepatic clearance of BSP occurred despite nonselective binding to liver homogenates and very low concentrations of binding proteins in liver cytosol. Analysis of the organic anion plasma disappearance curves suggest that the clearance of anions into bile in elasmobranchs is delayed disproportionately relative to hepatic uptake. Albumin-BSP infusions did not prevent selective hepatic uptake of [35S]BSP, although biliary excretion was delayed further. These studies demonstrate that transport systems for biliary excretion of organic anions evolved prior to migration of marine life from the sea and relatively independently of intrahepatic conjugation and organic anion-binding proteins.

Albumins↗
PubMed1976

Judged attractiveness in recognition memory of women's faces.

A series of 35 3 1/2 X 2 1/2-in., full-face photographs of female undergraduates were used as stimuli. Each subject rated the randomly presented photographs into high, medium, and low attractiveness and 2 hr. later subjects recognized photographs they judged most and least attractive significantly better than the more "neutral" faces when all were mixed with 10 previously unused control stimuli. Arousal and "distinctive cues" were discussed as possible explanations for the improved memory associated with attractive and unattractive faces.

Adult↗
PubMed1976

Selective hepatic uptake and biliary excretion of 35S-sulfobromophthalein in marine elasmobranchs.

The hepatic metabolism of 35S-sulfobromophthalein was studied in the free-swimming Elasmobranchs, Squalus acanthias (spiny dogfish shark) and Raja erinacea (small skate), to evaluate the physiological significance of biliary excretion of organic anions in marine vertebrates. Twenty-four hours after intra-arterial injection, 85.8 +/- 15.7% of the administered dose was recovered in bile and liver in dogfish and 78.4 +/- 9.9% in skates. More than 85% of BSP in bile was in unconjugated form in both species. Furthermore, selective hepatic uptake and biliary excretion of 35S-sulfobromophthalein occurred despite very little specific binding protein (Ligandin). These studies demonstrate that transport systems for biliary excretion of organic anions evolved before migration of marine life from the sea and independent of conjugation and organic anion binding proteins which facilitate biliary excretion of compounds such as 35S-sulfobromophthalein in higher vertebrates.

Animals↗