Effects of electrolytic bilateral symmetric lesions of the arcuate nucleus on the phagocytic activity and on the phagocytic response in rats.

Previous researches of Cluj-Napoca laboratories of Physiology (Benetato, Baciu et al., 1945, 1946, 1947) demonstrated that direct electrical stimulation of the tubero-mammillary area in dogs increases, in the following hours, the blood polymorphonuclears phagocytic activity. By contrast, electrical damage of the same region produces a depression of the basal phagocytic activity and a blocking of the phagocytic response (Baciu et al., 1958, 1988). In the present research we assumed there is a stimulating effect of the arcuate nucleus, located in this area, on the phagocytic activity of blood neutrophils. We used an anodal current to stereotaxically induce lesion of the arcuate nucleus in six rats. A control group of six animals was used. Five days later, phagocytic response was induced with a Gram negative bacterial extract given i.v. The results demonstrated a decrease of the phagocytic activity from 164.31 +/- 17 bacteria engulfed by 100 neutrophils in controls, to 138 +/- 12.8 in the lesioned group p < 0.05. Phagocytic response after five hours appears depressed in the lesioned group (138 +/- 12.8 to 156.25 +/- 13.3, p < 0.05). Similar results were obtained after 24 hours. In control animals the response is very significant after 5 and 24 hrs., respectively, (p < 0.001). In conclusion, the arcuate nucleus is moderately involved in sustaining the basal phagocytic activity of blood neutrophils. It has an important role in phagocytic response.

The effects of electroconvulsant shocks on phagocytic activity and on phagocytic response.

The influence of a single or several subsequent convulsant electroshocks at different time laps (2-4 day), over a month, on the phagocytic activity was studied on seven dogs. The electroconvulsant shock was performed with bitemporal electrodes, at a liminal electric power. Phagocytosis was studied in vitro with amidon particles in whole blood, incubated 1h at 37 degrees C. After 4 hours the phagocytosis increases in all animals and remains higher for 12 days. Later on the repeated shocks produce very different changes of the phagocytic activity, depending, not only on the stressor agent, but also on the animal particular reactivity, conditioned genetically and by its individual history.

Phagocytic response in rats following chemical sympathectomy with 6-hydroxydopamine.

Wistar rats were injected i.p. at 2, 4 and 7 days after birth with 6-OHDA (50 mg/kg). At maturity the phagocytic response of neutrophils was elicited by Escherichia coli (EC) lipopolysaccharide (LPS). Before and at 3 and 24 hours after the injection of LPS (1 mg/kg i.v.) the leucocyte (L) and neutrophil (N) counts and the phagocytic activity of N in blood against EC have been tested. In controls (6 female and 7 male rats) the number of N increases significantly after 3 h. The L and N responses were similar in controls and in treated (SyX) animals. In controls the percentage of phagocytic active N(PA) and the number of bacteria incorporated by 100 n(IB) shows significant rises at 3 h. In the SyX groups (7 females and 7 males) PA does not increase; the IB decreases significantly in females at 3 and 24 h. In conclusion chemical sympathectomy depresses the PR to LPS in rats; this suggests a stimulatory action of the sympathetic system on the phagocytic immune reaction. An immunological sexual dimorphism exists.