Motivated behavior and the estrous cycle in rats

(1) The estrous cycle in the rat may be used to study recurrent changes in motor behaviors and motivation which are strongly related to cyclic hormonal and CNS changes. (2) The peak in motivated behaviors occurs during a sharply defined period on the night between proestrus and estrus and is evident in facilitated wheel-running, lordosis, and intracranial self-stimulation. (3) Behaviors without a clearly motivated character do not show an estrous cyclicity. (4) The estrous cyclic variation in intracranial self-stimulation was observed at a specific locus — the pars campacta of the substantia nigra. (5) A neurochemical link between sexually motivated behavior, wheel running and intracranial self-stimulation is suggested. This link is in part dopaminergic but is probably also activated by many other systems.     

Les onze propositions issues des 3es États généraux des malades du cancer et de leurs proches de la Ligue contre le cancer

Sans résumé     

Measuring behaviour: The tools and the strategies

Animal behaviour can be viewed as a stream of elements, which, once accurately described, can be counted and timed. Data acquisition techniques and tools are reviewed, and some strategies for collection and analysis of data using PC computers are suggested. Automated instruments are not satisfactory for the study of complex behaviour and as such systemic observation remains irreplaceable. IBM PC-type computers, with a wide range of analytical software (e.g., spreadsheets, statistical packages, technical graphics), are practical for data acquisition. Several systems which can satisfy different applications are reviewed. Some systems can communicate with a videorecorder, a facility which remarkably increases the accuracy of measurement; this is essential for meaningful analyses of the internal structure of behavioural streams (sequences, time patterns) or communication processes. The power of new tools enables behavioural measurement with the necessary complexity to allow a whole new set of questions to be addressed. However, it also increases demands for meaningful content and analysis of data.     

Single odor-sensitive channels in olfactory receptor neurons are also gated by cyclic nucleotides.

Olfactory transduction is thought to occur by processes that are mainly restricted to the specialized cilia emanating from the distal end of the receptor neuron's single dendrite. The involvement of a cAMP-based second messenger system seems likely, and a cyclic nucleotide-sensitive current has been recorded in patches of membrane from the cilia. However, the small diameter of the cilia and the high density of channels within the membrane limit the application of the patch recording technique in the cilia. We have found that the cAMP-sensitive channels also exist at a much lower density within the far more accessible dendritic membrane. Recording from on-cell patches, we have observed single-channel activity in response to extracellularly applied odor substances. The channels have a single-channel conductance of 40 pS and a reversal potential near 0 mV. These same channels are activated by treatments that elevate intracellular cyclic nucleotide concentrations. The results provide a direct demonstration that the cyclic nucleotide-gated channel is the conductance pathway for the odor-elicited current.     

The impact of sequential quality assessment exercises on laboratory performance: the multicentre ECAT Angina Pectoris Study. Report from the European Concerted Action on Thrombosis and Disabilities (ECAT)

As an adjunct to a European multicentre prospective study, five quality assessment (QA) exercises, spanning a period of 2.5 years, were undertaken. In these, fifteen laboratories from eight countries each performed ten haemostatic factor assays. The design of the QA exercises allowed the between-duplicate, between-day and between-laboratory coefficients of variation (CVs) to be calculated. The between-duplicate CV decreased by a factor of one quarter, and the between-day CV by a factor of one third, over the five exercises. The activated partial thromboplastin time (APTT) assay consistently showed the lowest CVs, while there was notable improvement in the between-day CVs for von Willebrand factor related antigen (vWF R:Ag) and factor VIII clotting activity (VIII:C). However, the between-laboratory CV, assessing extent of agreement between the different laboratories, did not apparently improve over the five exercises. Thus, while QA exercises may be very useful in improving the performance of haemostatic assays according to criteria which an individual laboratory can assess, improving agreement on haemostatic assay results between laboratories may be more difficult to achieve.     

Double-blind, placebo-controlled comparison of clonazepam and alprazolam for panic disorder

To test the reported antipanic efficacy of clonazepam, the authors randomized 72 subjects with panic disorder to 6 weeks of treatment with either alprazolam, clonazepam, or placebo. Endpoint analysis demonstrated a significant beneficial effect of both active treatments, but not placebo treatment, on the frequency of panic attacks, overall phobia ratings, and the extent of disability. Comparison of the two active treatments revealed no significant differences and no consistent tendency for one agent to be favored over another, although power to detect small differences was limited. Sedation and ataxia were the most common side effects reported, but these effects were mild and transient and did not interfere with treatment outcome. The results of this double-blind, placebo-controlled trial are consistent with previous reports of clonazepam's antipanic efficacy.     

Lithium treatment of chronic hair pulling

Ten patients with chronic hair pulling received trials of lithium carbonate of 2 to 14 months' duration. Eight patients demonstrated decreased hair pulling and mild to marked hair regrowth. Three responders experienced increased hair pulling subsequent to discontinuation of lithium treatment. Lithium's effect on hair pulling may be related to its observed benefits in treating aggressivity, impulsivity, and mood instability.