1-7
A Neurophysiological Study on the Sympathetic Premotor Nuclei in the Pons and Medulla Oblongata
by Yasuhiko Kira, Taku Ogura,Yasuo Mikami, Shunzo Aramaki, Fumihiko Nakanishi,Toshikazu Kubo

The aim of this study was to neurophysiologically demonstrate the activities of the premotor nuclei of sympathetic vasomotion, by capturing the diachronic changes in the action potentials which are generated in the pons and medulla oblongata. To do so, ten male Wistar rats weighing 300g were used as subjects. Microelectrodes were inserted in the muscular branch of the sciatic nerve and the ventral side of the pons and medulla oblongata, and the muscle sympathetic nerve activity (MSA) was induced. The regular spontaneous action potentials, which synchronize with muscle sympathetic nerve activity, were observed in the rostral ventrolateral medulla oblongata (RVLM), and the differences among the action potentials of individual cells of the RVLM region noted. Autonomic postganglionic nerves are controlled in turn by preganglionic nerves that originate from specific nuclei in the medulla. These nerves directly influence cardiovascular function by regulating the rate and force of contraction of the heart and the diameter of blood vessels. RVLM cells in fact exert a widespread control over the sympathetic outflow. We conclude from the experiment that premotor nuclei of sympathetic vasomotion exist in the RVLM.

9-16
Measurements of Three Ocular Parameters in the Göttingen Minipig
by Lisbeth Sandfeld Nielsen and Nanna Marie Lind

The use of laboratory pigs has increased dramatically in the last decade, and this study supplements the basic ocular anatomical and physiological characterisations already carried out on laboratory pigs. Pigs are frequently used as models of human ocular diseases due to the similar anatomy and physiology of the ocular structures of the pig as compared to humans, but refractive error has not been investigated systematically in the Göttingen minipig. We measured refractive status, corneal power and axial length in a sample of 30 adult Göttingen minipigs including both sexes. The uncorrected mean refractive error was +1.3 dioptres (D) with a standard deviation (SD)± 2.3 D.The mean corneal power was 44.1 D (SD±1.5D) and mean axial length less than 19 mm. No statistically significant difference was detected between the right and left eye values, with respect to colour of iris, or between genders (p<0.05). In spite of the smaller axial length, measures of refractive error and corneal power in the Göttingen minipig are comparable to human values. This information should prove useful when using Göttingen minipigs as models for human ocular conditions or in research involving vision or other ophthalmic aspects of the Göttingen minipig. Also, the refractive status of the animal can be of importance when using pigs in cognitive tasks, mainly because of the probable lack of accommodative reflex in pigs. If visual stimuli are presented at a short distance, clinical, emmetropia or myopia in the experimental animals would be desirable; in the present cohort of examined pigs, 60% fulfilled these criteria.

25-30
Effects of Neostigmine Methylsulfate on Enzyme Activity of Acetylcholinesterase in Rat Serum, Plasma, Muscle and Liver in vivo
by H. Demir and V. Turkoglu

This study was designed to investigate the effects of neostigmine methylsulfate on enzyme activity of acetylcholinesterase (AChE) in rat serum, plasma, muscle and liver were investigated in vivo. Twelve Sprague-Dawley Albino male rats, weighing 150-200 g were housed in two groups, each group containing six rats. A single dose (0.05 mg/kg) of neostigmine methylsulfate was injected intramuscularly to the treatment rats. Control rats were given only the same amount of physiological saline. Blood samples for enzyme activity were obtained by cardiac puncture under ether anesthesia one, three, and six hours after the treatment. The tissues were dissected six hours after the treatment. The present study indicated that neostigmine methylsulfate possessed an inhibitory effect on AChE activity in serum, plasma, muscle and liver with the elapse of time. However, the greatest inhibition was found six hours after the injection.

33-37
Effect of Repeated Confined Single Housing of Young Pigs on Faecal Excretion of Cortisol and IgA
by Felix Royo, Karin Lyberg, Klas S. P. Abelson, Hans-Erik Carlsson and Jann Hau

During 48 days four young male, castrated Yorkshire x Landrace pigs (growers) were singly housed alternatively in standard pig pens (4 x 6 days) and metabolic cages (4 x 6 days). The faecal excretion of cortisol metabolites and immunoglobulin A (IgA) was quantified by enzyme-linked immunoabsorbent assays (ELISAs). The first stay in the metabolic cage was associated with an increase in faecal cortisol levels, which may be interpreted as a symptom of acute stress. But when the pigs’ visits to the metabolic cages were repeated, the faecal cortisol generally reverted to fairly low levels. Concomitantly, faecal IgA excretion decreased steadily during the study period suggesting sustained stress. The body weight gain was lower during periods when the pigs were housed in metabolic cages than when they were in pens. These results suggest that metabolic cages caused a continued stress condition in pigs. One pig showed consistent high IgA excretion and a smaller decline in body weight gain during periods in the metabolic cage than the other pigs. This pig thus appeared to be less stressed than the other pigs, but maintained high cortisol levels throughout the study period when housed in the ordinary pen. This indicates that cortisol may have a protective effect against the stress caused by housing in metabolic cages.

41-43
House Musk Shrews (Suncus murinus) Do Not Copulate in the Light Period when First Paired in the Dark
by Haruo Hashimoto and Toru R. Saito

The copulatory behavior pattern of house musk shrews paired for 24 h starting at either 09:00 (light) or 20:00 (dark) was investigated. Ejaculatory behaviors were observed in both light and dark periods, when mating was started at 09:00. However, the males ejaculated only in the dark period when they were paired at 20:00.