An interactive approach to GLP training.
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Biomedical subjects
Publications and source records attributed to A S Russo.
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Studies with electrical brain stimulation suggest that the dorsal periaqueductal grey matter (DPAG) is related to anxiety and to the anti-aversive effects of benzodiazepines (BZD) compounds. However, direct stimulation of the brain may prevent conclusions about the role of specific regions in the control of normal behaviour. In the present study we employed the elevated plus-maze, an ethologically based model of anxiety, to investigate the role of BZD receptors located in the DPAG in anxiety and in the anxiolytic effect of systemically injected BZD. The results showed that midazolam (20-80 nmol), a BZD agonist, dose-dependently increased the percentage of entries and time spent in open arms when microinjected into the DPAG. The effect of midazolam (80 nmol) was antagonized by flumazenil (80 nmol), a BZD antagonist, microinjected into the DPAG 10 min before the agonist. FG 7142 (20-80 nmol), a BZD partial inverse agonist, decreased time spent in open arms at the dose of 40 nmol and the number of open arms entries at all doses when microinjected into the DPAG. The microinjection of flumazenil (80 nmol) into the DPAG failed to antagonize the anxiolytic effect of systemically injected diazepam (2.5 mg/kg). These results strengthen the idea of an involvement of BZD receptors located in the DPAG with anxiety. They also suggest that the DPAG is not the only structure responsible for the anxiolytic effects of systemically injected BZD.
In order to investigate the role of the dorsal periaqueductal grey (DPAG) area in the anxiolytic effect of benzodiazepines male Wistar rats (N = 10), weighing 200-250 g at the time of surgery, were microinjected into this structure with midazolam (80 nmol) and submitted to the elevated plus-maze, an ethologically based model of anxiety. Midazolam significantly increased the percentage of open arm entries from 32.4 +/- 4.6 (control) to 49.5 +/- 3.0 and of time spent in the open arms from 21.0 +/- 4.5 (control) to 35.6 +/- 4.8 without affecting the total number of entries into either open or enclosed arms. This effect typifies an anxiolytic effect in the test and was antagonized by the benzodiazepine receptor antagonist flumazenil (80 nmol) microinjected into the same site 10 min before the midazolam (80 nmol) microinjection. Microinjection of flumazenil alone had no effect. These results provide additional evidence for the participation of the DPAG in the physiopathology of anxiety and suggest that it may be a site for the anxiolytic effect of systemically injected benzodiazepines.
The true measure of any successful quality endeavor is the final product. The final product generated at contract facilities conducting nonclinical studies is the final report. This should be accurate, complete, and consistent with regard to the raw data, and in compliance itself. The final report resulting from studies conducted at contract laboratories should be reflective of the collaborative efforts of sponsor and laboratory staffs. The dual interaction of the respective Quality Assurance Units (QAUs) in ensuring that optimal study performance is maintained from initiation through final report submission is of paramount importance. Key to any productive sponsor/contract laboratory relationship is communication. The multidirectional flow of information inherent in the conduct of nonclinical studies must be managed to maximize the strengths of the principals involved, while at the same time assuring that consistent emphasis is placed on team focus. Although the role of the QAUs representing the contract facilities and the sponsor both ensure the quality of study conduct, and ultimately the final product, their respective approaches may be from different perspectives. The contract QAU's primary focus is the specific study conduct, including appropriate inspections of ongoing critical phases and audits of raw data and reports, along with compliance to site Standard Operating Procedures (SOPs), protocols and sponsor requirements. On the other hand, sponsor QAUs focus mainly on overall study conduct, assurance that contract QAUs are operating effectively, and ensuring that sponsor monitors are communicating adequately with contract facility personnel. Open communication between the respective QAUs is the most productive and useful way of ensuring that all quality criteria are met.(ABSTRACT TRUNCATED AT 250 WORDS)