Dextrorphan effects on cocaine and brainstem perturbation

Dextrorphan is a noncompetitive blocker of N-methyl-D-aspartate (NMDA) receptors. Since NMDA blockers are known to reduce the locomotor stimulatory and toxic effects of cocaine, it was speculated that dextrorphan would attenuate cocaine-induced behavioral excitatory motor activity associated with and without mechanical perturbation of the brainstem. Technique: Motor activity was recorded following dextrorphan and/or cocaine challenge in 25 SHR rats. Ten were naive subjects. Mini-osmotic pumps delivering cocaine (2.5 mg/0.49 ul/hr) were placed in 15 subjects, and infusion was halted after the third infusion day. On the fifth day either a dextrorphan (25 mg/kg, subcutaneous) or a dextrorphan and cocaine (40 mg/kg, intraperitoneal) challenge was done. Ten rats had bipolar electrode implants in the bilateral brainstem. Five were treated with DC current lesions in each of 12 days over a 3-week period. The effects of brainstem lesions on escape behavior were also evaluated in those five subjects. Results: In the naive subjects, dextrorphan reduced motor activity (P=.0001), whereas combined cocaine and dextrorphan increased motor activity (P=0.04). In lesioned subjects, dextrorphan decreased motor activity (P=0.0001). In electrode implant subjects, combined dextrorphan and cocaine challenge decreased the motor activity (P=0.04). Hyperactivity in the electrode implant group was greater than in the lesioned subjects. Midbrain electrolytic lesions attenuated escape behavior. A variety of behaviors were produced by brainstem lesions. Conclusions: Dextrorphan and brainstem lesions reduced motor hyperactivity and escape behavior. In electrode implant subjects dextrorphan counteracted the expected cocaine excitatory motor effects. Dextrorphan did not activate nor facilitate seizures.     

Book Reviews

Religions sans Frontières? Present and Future Trends of Migration, Culture and Communication Roberto Cipriani, ed., for the Research Committee “Sociology of Religion”; of the International Sociological Association, Rome, Presidenza del Consiglio del Ministri, Dipartimento Per L'Informazione e L'Editoria, 1994 384 pp. no ISBN on book

Worldviews in Transition: An Investigation into the New Age Movement in South Africa Chrissie Steyn, 1994 Pretoria: University of South Africa (Studia Originalia 22) xvi + 367 pp., R79.00 or £14.86 (+ p&p) ISBN 0–86981–845–7

Women and Missions: Past and Present. Anthropological and Historical Perceptions Fiona Bowie, Deborah Kirkwood & Shirley Ardener, eds, 1995 Berg: Providence/Oxford xx + 279 pp., plates, £14.95 ISBN 9–780854968725

Syncretism/Anti‐Syncretism: The Politics of Religious Synthesis Charles Stewart & Rosalind Shaw, eds., 1994 London: Routledge 215 pp., £37.50 (hb), £12.99 (pb) ISBN 0–415–11117‐X.

Beyond the Basilica: Christians and Muslims in Nazareth Chad F. Emmett, 1995 Chicago and London: University of Chicago Press xix + 303 pp., £17.50 US$22.00 pb, ISBN 0–226–20711–0

Islamic Britain: Religion, Politics and Jolentity among British Muslims Phillip Lewis, 1994 London: I. B. Tauris & Co. 250 pp., £11.95 ISBN 1–85043–861–7

Religion & Revelation: A Theology of Revelation in the World's Religions Keith Ward, 1994 Oxford: Clarendon Press 350 pp., £40 hb, £13.95 pb ISBN 0–19–826466–6 & 826375–9

Religiöser Pluralismus oder christliches Abendland? Herausforderung an Kirche und Gesellschaft Reinhart Hummel, 1994 Darmstadt: Wissenschaftliche Buchgesellschaft 223 pp., DM39.80, FR40.80, ÖS311.00 ISBN 3–534–11717–4

A Short History of Judaism Lavinia & Dan Cohn‐Sherbok, 1994 Oxford: Oneworld Publications viii +148 pp., £5.95 ISBN 1–85168–069–1

Unforgotten Fragments Beryl Pogson & Others, compiled by Lewis Creed, 1994 York: Quacks Books 352 pp., £15.95 ISBN 0–948333–29–4

Centenary Fragments Beryl Pogson & Others, compiled by Lewis Creed, 1994 York: Quacks Books 379 pp., £15.95 ISBN 0–948333–36–7

A Plain Guide to Bible Theology: A Realistic Approach L. G. Hardinge, 1993 Swansea: Abertawe Desktop (OR: L G Publication, 1994) 217 pp., £10.50 (pb) ISBN 0–9524013     

Neonates' heart rate,sucking rhythm,and sucking amplitude as a function of the sweet taste

In previous studies of human newborn sucking, the effects of increasing fluid sweetness and/or volume included a decrease in sucking rate within sucking bursts and, paradoxically, an increase in heart rate. To determine whether the heart rate increase can be attributed to increased sucking amplitude for sweeter fluids, sucking and heart rates of 20 full-term infants were studied. Half sucked for three consecutive 2-min periods, first receiving small drops of water for each suck, then no fluid, then 15% sucrose. The other half experienced the reverse order. The results for sucking and heart rate were consistent with previous studies; sucking rates within bursts were slowest for sucrose and fastest for no fluid. Heart rate was higher for sucrose than for the other fluid conditions, however, only in the water-first group. The heart rate increase was significant on statistical tests which controlled for sucking amplitude as well as for several other motor variables. Sucking amplitude itself varied with fluid sweetness in the water-first group only, in which it was highest for water. There were more total sucks, longer sucking bursts, and less time between successive bursts under the sucrose condition. Multivariate statistics helped establish a set of dependent variables—sucking rate within bursts, total number of sucks, and heart rate—which most parsimoniously describes the effects of fluid sweetness. A hedonic explanation of the response of newborns to sweetness is thus reiterated.     

Phonological recoding: Is the regularity effect consistent?

An attempt was made to distinguish between the dual-access and the activation and synthesis models of word identification. Word regularity and consistency were factorially manipulated. In two experiments lexical decisions were required, and in two the task was word naming. Within each task, comparisons were made of the effects achieved by manipulating the degree to which subjects were free to rely on a phonological, rather than a visual, stimulus code. The results suggested that lexical access generally involves the activation of lexical entries that are visually similar to the target, but that subjects do favor a phonological code when the task requires the naming of words only. The data were interpreted as requiring a model incorporating elements of both the dual-access and the activation and synthesis frameworks.     

Reinforcement effects on intrinsic interest: A classroom analog

The potential undermining effects of a reinforcement program were examined in two studies with kindergarten-first grade children. The procedures were designed to provide an analog to typical classroom incentive programs. In one study, the subjects' initial interest in the target activity (coloring) was low, whereas in the other study it was reasonably high. In neither case was an undermining effect evident in follow-up observations.     

Developmental tasks of terminally ill patients

Erikson's epigenetic stages provide a conceptual map of how a person responds to the knowledge of having a terminal illness. The patient initially reworks developmental tasks that have been resolved and then works at an accelerated pace to accomplish tasks that remain ahead. This acceleration is an attempt to attain a wholeness of self and life in light of the threat of imminent death and self-perceived shortened life span.     

Vocalization and looking behaviour of Down's syndrome infants.

The effect of contingent and non-contingent vocal stimulation on vocalization and looking behaviour was investigated for 10 Down's syndrome infants. There were two experimental sessions consisting of four stages, namely 1 min base-line, 1 min experimental condition, a further 1 min base-line and a final 2 min experimental condition. Maternal vocal stimulation was contingent upon infant vocalization for the experimental conditions of one session and was presented every 10 s independent of infant vocalization for the experimental conditions of the other session. Neither condition increased infant vocalization but there was a significant decrease in looking at mother during the base-line stages which followed maternal vocalization (F = 5.07, d.f. = 4, 28, P less than 0.01). It is suggested that looking behaviour may be an important indication of competence in pre-linguistic social communication for developmentally delayed infants.     

Interactive activation accounts of morphological decomposition: finding the trap in mousetrap?

Many accounts of the processing of morphologically complex words have been elaborated within the interactive activation model of word identification. Conceptually, this model adopts a "segmentation-through-recognition" approach to morphological decomposition, which assumes that a complex word activates representations of constituent morphemes as well as the representation of the whole word. However, a detailed consideration of the assumptions of interactive activation frameworks reveals that current implementations of the model are incapable of achieving segmentation-through-recognition.     

Using student-managed interventions to increase homework completion and accuracy

We examined the effectiveness of self-managed individual and group contingency procedures in improving the completion and accuracy rates of daily mathematics homework assignments. A group of sixth-grade students having homework difficulties in mathematics were selected for the study. There was substantial improvement in the amount of homework completed over baseline for a majority of the students, whereas the results for accuracy were mixed. Students who participated in the self-management training made significant gains on standardized measures of academic achievement and curriculum-based measures of classroom performance. Parents also reported significantly fewer problems associated with homework completion following the intervention. Students who were allowed to select their own performance goals made superior improvements in the number of homework assignments returned compared to students who were given a specified goal by the classroom teacher. Parents, subjects, and the classroom teacher responded positively on consumer satisfaction measures following termination of the study.     

Tests of three hypotheses regarding the predictors of delinquency

Three hypotheses regarding the predictors of criminal activity in children and adolescents were assessed. These dealt with family, peer, and attitudinal variables, and they were explored in relation to indices based on seriousness of criminal activity and reoffending. The data were based on a sample of 338 youths who had been convicted of crimes and received probation or custody dispositions. The results provided general support for a model implicating family, peer, and attitudinal variables in youthful criminal activity. They did not, however, provide support for hypothesized interactions between family relationship and family structuring dimensions or between family relationship and peer association variables. The results did support an hypothesis regarding the independent contribution of an antisocial attitudes variable to the prediction of criminal activity.Funding to support this research was provided by the Children's Services Branch of the Ministry of Community and Social Services (Ontario), Carleton University, and the London Family Court Clinic. Thanks are extended to Penny Faulkner, Mary Ann Robblee, Suzanne Bell, and Natalie Gabora for their assistance on the project. Members of the Ministry Research Advisory Committee are also thanked for their contribution.