Decerebration induced by surgical transection of cerebral ganglion of crayfish

Background: Since the neural structures of the crayfish brain closely resemble their equivalent in the mammals. This can be suggested by observing the similarity that exists in the brain divided by the surgical transection of the crayfish brain in which the protocerebrum remains attached to the first two cranial nerves, findings also described by Frederic Bremer in 1935 in cats with cerebral transection.Methods: Total 11 Adult male crayfish were trained to respond with defense reflex, the animals were placed in water at 0°C, remained without any movement, and subsequently through a small incision of 3 mm in diameter in the medial antero region and dorsal cephalothorax region, a surgical section of the cerebral ganglion was performed. Immediately after surgery, metal microelectrodes were implanted to collect the activity of the photoreceptors and visual fibers.Results: Once the defense reflex begins to recover in previously decerebrated crayfish, it means that it shows signs of reconnection. The isolated protocerebrum with the deutocerebrum olfactory lobe remain alive for several days and the neuronal connections were reestablished, as measured throughout the bilateral defense activity. The defense reflex was observed in all animals and then recovered after surgery.Conclusions: The crayfish is an excellent model to work the visual activity, all coding of visual information was suppressed in de-cerebrated crayfish. The recovery of the neural disconnection is observed from 40 days, where the defence reflex appears again before visual stimuli.

The impact of the new derivative of nicotinic acid with anti-hypoxic activity on the functions of the central nervous system

The aim of the work was to study the effect of the complex compound of nicotine acid with antihypoxic activity under the code πQ-1043 on the function of the central nervous system. The experiments were performed on male mice of the SHR line. Influence of the compound on the function of the central nervous system was evaluated in the tests “open field”, conditioned-defense reflex of avoidance and corazole seizures. It was found that the compound πQ-1043 at a dose of 25 mg/kg increases emotional reactivity and reduces the coefficient of mobility of mice in the “open field” test, increases the latent time of the conditionally defensive reflex of avoidance, inhibits the development of seizures and increases the life expectancy of animals after administration of corazole. Such changes in the studied parameters indicate that the compound πQ-1043 has a depressing effect on the central nervous system function. It is assumed that the identified effect may be one of the components in the mechanism of antihypoxic action of the compound.

The Philosophical Concepts in Ryszard Otowicz’s Bioethics

This article presents a general overview of philosophical issues undertaken in the work of Richard Otowicz (1953–2003), Jesuit and Professor of Moral Theology at the Pontifical Faculty of Theology in Warsaw. Within the set of views developed by him, the theological perspective undoubtedly assumes pride of place. Often, however, he refers to philosophical issues from which, in his opinion, one cannot escape—issues that bear directly on human life. What is especially striking is Otowicz’s hypothesis that bioethics is a kind of self-defense reflex of mankind, who are attempting by means of it to intellectually grasp the issues relating to the unlimited expansion of technology. Developments and changes observed in the world are forcing humanity to rethink very fundamental issues, such as interpersonal relationships or the relationship of man to nature.

Beaded nerve terminals in feline laryngeal mucosa

To investigate the mechanism of airway defense reflex, beaded nerve terminals were studied by immunohistochemical techniques. In the supraglottic region the density of PGP 9.5–immunoreactive nerve fibers was the highest at the base of the glottic surface in the epiglottis, and in the glottic region it was the highest in the arytenoid region. In the subglottic region the number of positive nerve fibers was less than the number at the base of the glottic surface in the epiglottis, and when the laryngeal mucosa was processed with NaOH to dissolve the epithelium, it was possible to observe beaded nerve terminals more clearly. These beaded nerve terminals were found just beneath, in the epithelial basement membrane. Electron microscopic examination of beaded nerve terminals revealed a large quantity of secretory granules and mitochondria, suggesting that their structure is similar to that of nerve terminals. Thus these beaded nerve terminals may function as mechanoreceptors. (Otolaryngol Head Neck Surg 1998;119:113–6.)