Potentiation of the pressor response to stress by tolbutamide in dogs

Tolbutamide has previously been shown to amplify the pressor effects of “exogenous” catecholamines in conscious dogs, possibly due to sensitization of the α₁-adrenoreceptor-mediated vasoconstriction. The objective of this study was to examine if tolbutamide also amplifies the pressor effects of “endogenous” catecholamines released during psychological stress (classical Pavlovian aversive conditioning). Experiments were conducted in β-adrenoreceptor-blocked (propranolol, 1 mg/kg, i.v.) conscious dogs (n=4) trained in classical aversive conditioning. Conditioning was accomplished by following a tone (CS+) with a 1/2 second shock; another tone (CS-) was not followed by any shock and served as control. With saline pretreatment, aversive conditioning (i.e., CS+) increased mean arterial pressure (MAP) only by approximately 4.7% when compared to CS-, whereas with tolbutamide (45 mg/kg, i.v.) pretreatment, the increase in MAP induced by CS+ beyond what was induced by the CS- (approximately 6.2%) was significantly (p<0.05) larger than that with saline pretreatment. In isolated canine femoral arterial segments (n=4), the vasoconstrictor effect of phenylephrine (an α₁-agonist) at 5×10^?6M (which was the EC₅₀ value) was amplified by 2×10^?2M of tolbutamide from 54.0±2.0% to 66.9±2.1%. In conclusion, tolbutamide amplifies the pressor effects of “endogenous” catecholamines in conscious dogs, possibly by sensitization of the α₁-adrenoreceptor-mediated vasoconstriction. This mechanism of action is novel and has not been reported with other agents.     

The use of partial temporal information in dating personal events

Memory & Cognition - The use of different types of partial temporal information is shown to affect dating accuracy and the distribution of errors in event dating. Several different types of...     

Some hypotheses concerning the evolution of polysemous words

The evolution of polysemous words is examined in three studies. Study 1 indicates that older words are more polysemous than recent words, and that frequently used words are more polysemous than infrequently used words. These effects were replicated, controlling for word concreteness (Study 2) and evaluation (Study 3), using two other samples of words. If words evolve additional meanings through metaphor (MacCormac, 1985), then variables (such as concreteness and evaluation) that play a role in metaphor may mediate the evolution of polysemy. The correlation between concreteness and polysemy was negligible (Study 2). As hypothesized, evaluation is a significant predictor of polysemy: Negative words are more polysemous than positive words, and relatively neutral words are more polysemous than evaluatively extreme words. These findings are consistent with the notion that polysemous words evolve, in part, through metaphor.     

The Future of Psychology in Departments of Psychiatry

Health care reform has put increasing pressure on faculty of medical schools to become self-supporting. Opportunities for clinical revenue will decrease, but psychologists who are able to generate research funding will become increasingly competitive, albeit as mercenaries, i.e., capable of paying their own way plus generating a profit to support departmental operations and educational programs. Changes in the health care system signal an end to psychiatry's paternalistic relationship to psychology and present opportunities for psychology proactively to influence its future role in health care. Research, political action, and revised scientific mission, models, and roles represent important strategies in the redefining of psychology as a basic science and major profession in health care.     

Isoluminance and contingent color aftereffects

In the typical induction of the orientation-contingent color aftereffect (CCAE), the stimuli are composed of elements that differ in both color and luminance. Three experiments are reported that show that chromatic contrast between stimulus elements is insufficient for the induction of the orientation-CCAE and that luminance contrast is necessary. These experiments expand on previous research concerned with the role of luminance contrast in the induction of orientation-CCAEs by eliminating alternative explanations.     

Late Adolescents' Experiences With and Attitudes Toward Videogames1

A total of 229 late adolescents (a large majority 15 to 19 years of age) completed a questionnaire that assesses a broad range of videogame-relevant experiences, preferences, and attitudes. Videogame playing was found to be a more popular, and a more highly regarded, activity among males than females. Gender differences were also found in participants' ratings of their motivations for playing videogames, their evaluations of particular characteristics of videogames, and their selection of their “most favorite” videogame. The differences between frequent and infrequent videogame players appeared to be limited to differences in the extent to which videogame playing is pursued and evaluated as a positive leisure activity, rather than reflecting broad differences in interest or personality. Some relations were found between participants' self-reported personality characteristics (i.e., self-esteem, empathy, conscientiousness, and introversion) and their attitudes toward videogames.     

Positive Psychological States in the Daily Life of a Sample of Working Women

This study of a sample of working women investigated where positive experiences were derived from in everyday life, focusing on the domains of work and nonwork (leisure). It examined how aspects of the situation, in terms of principal environmental influences in work and leisure, and the person, in terms of locus of control, were associated with positive subjective states and psychological well-being. The study employed questionnaires and also the experience sampling method. The results showed that both work and leisure were important for positive psychological states and that internal locus of control was associated with greater enjoyment, interest, feelings of immediate control, intrinsic motivation, life satisfaction, and affective well-being and a number of principal environmental influences.