Changes in the Leukocyte Distribution and Surface Expression of Adhesion Molecules Accompanied with Hypothalamically Induced Restlessness in the Cat

Abstract

One type of emotional behavior called restlessness occurs when the anteromedial hypothalamus is stimulated in cats. We examined the changes in the distribution and surface expression of adhesion molecules in leukocytes accompanied with restlessness. Mature female cats were used for this study. The cats were stimulated with 60 Hz sine wave train pulses (20–90 μA, 10 s in duration, at 5-min intervals) for 60 min. Samples of blood were collected from 30 min before stimulation up to several hours after the final stimulation. The number of granulocytes increased just after stimulation, while at the same time the expression of L-selectin decreased. On the other hand, the number of CD4+ and CD8+ T lymphocytes decreased at 1–2 h after the end of the stimulation, while the expression of L-selectin increased. In addition, the expression of LFA-1 and VLA-4 did not change. These data suggest that hypothalamically elicited restlessness is thus accompanied by a leukocyte distribution change, which might be mediated by changes in the expression of L-selectin on leukocytes. Plasma cortisol increased during stimulation in restlessness. However, during in vitro culture experiments, cortisol did not alter the expression of leukocyte L-selectin which thus indicated that cortisol does not directly affect the surface expression of L-selectin. These results thus suggest that hypothalamically induced restlessness is a useful stress model for psychoneuroimmunological studies.

Changes in the Leukocyte Distribution and Surface Expression of Adhesion Molecules Induced by Hypothalamic Stimulation in the Cat

“…In our previous study, we reported that AH stimulation induced changes in the leukocyte distribution and surface expression of adhesion molecules (Mori, Kaname, Sumida, Tanaka, Kubo, Tashiro, & Nomoto, 2000). Therefore, in our present study, we examined the relationship between VMH stimulation and changes in the leukocyte distribution and surface expression of adhesion molecules.…”

“…The methods employed in this study were almost the same as those used in our previous study (Mori, Kaname, Sumida, Tanaka, Kubo, Tashiro, & Nomoto, 2000). Therefore, the following paragraphs describe only the primary aspects of the methodology.…”

The Effects of a Switch-Off Response Accompanied by Hypothalamically Induced Restlessness on Immunoendocrinological Changes in Cats

“…Hypothalamic stimulation was given to each cat at 5-min intervals for 60 min, and then the cat turned off the stimulation within 2.0 s for a total of 12 stimulations. The times and intervals of stimulation were the same as those employed in our previous study [31].…”

“…Peripheral blood was sampled from the external jugular vein without anesthesia while the neck of the cat was held gently [31]. Soon after the collection of peripheral blood, both catecholamine and cortisol assays were performed.…”

“…Moreover, restlessness behavior has been found to increase the concentrations of both plasma epinephrine and cortisol, which are considered to be major hormones that increase during stressful situations. Furthermore, when restlessness behavior is evoked repeatedly and chronically, hypertrophy of the adrenal gland, atrophy of the thymus and mucous damage in the gastric wall can be induced [27][28][29][30][31]. As a result, hypothalamically elicited restlessness behavior is closely related to the physical reactions that are observed in stressful situations.…”