Acute and Chronic Effects of Superior Cervical Ganglionectomy on in vitro Mitogenic Responses of Lymphocytes from Submaxillary Lymph Nodes of Pituitary-Grafted Rats

Abstract

Male rats were grafted an anterior pituitary within breast muscles or received a sham operation on day 5 of life. At the 60th day of life, the sympathetic denervation of rat submaxillary lymph nodes was achieved by a bilateral sympathetic superior cervical ganglionectomy (SCGx; at 15.00 h). Rats were killed either 18 h later (acute SCGx) or after 12 days (chronic SCGx) to measure lipopolysaccharide (LPS)- and concanavalin A (ConA)-induced cell proliferation in submaxillary lymph nodes, submaxillary lymph node cellularity and serum prolactin levels. In control rats, acute SCGx significantly augmented LPS or ConA activity on lymph cells while chronic SCGx had no effect. In pituitary-grafted rats, acute SCGx depressed the mitogenic effect of LPS or ConA whereas chronic SCGx augmented it. A global inhibitory effect of surgical stress on submaxillary lymph node cellularity was found in rats subjected to SCGx or its sham operation 18 h earlier. Serum prolactin levels increased significantly in pituitary-grafted rats, particularly in those subjected to chronic SCGx. In pituitary-grafted rats, a significant effect of acute SCGx was apparent, with serum prolactin levels augmenting about twice in sham-SCGx rats, and to a significantly less extent in acute SCGx rats. The results provide further evidence of the immunomodulatory role of local sympathetic nerves in submaxillary lymph nodes.

Psychoimmune Neuroendocrine Integrative Mechanisms Revisited

“…Such a differential effect of acute and chronic ganglionectomy was apparent only in rats made hyperprolactinemic by a pituitary graft. In these animals, acute ganglionectomy depressed and chronic ganglionectomy augmented the mitogenic activity of LPS or Con A [50]. These observations were similar to the previously reported increase in plate-forming cell response in the submaxillary lymph nodes of chronically superior cervical ganglionectomized mice challenged with sheep red cells and to the decrease in the response found during the anterograde degeneration phase after ganglionectomy (within 24 h after surgery) [51].…”

“…These observations were similar to the previously reported increase in plate-forming cell response in the submaxillary lymph nodes of chronically superior cervical ganglionectomized mice challenged with sheep red cells and to the decrease in the response found during the anterograde degeneration phase after ganglionectomy (within 24 h after surgery) [51]. The authors hypothesized that the high prolactin levels led to increased immunocompetence, resembling somewhat the process triggered by the immune challenge, thus allowing the effect of sympathetic denervation to emerge [50]. Together with reports dealing with alteration of antibody responses of lymph nodes and spleen following local sympathectomy [52][53][54], with the evidence that the diurnal changes in submaxillary lymph node cell proliferation is related to a circadian signal conveyed by the local autonomic neurons [55] and with indication that immunosuppression diminished during acute stress in rats partly due to changes in neural signal traffic in local sympathetic nerves [56], the results strongly support the concept that the autonomic innervation of immunocompetent organs is a very important channel for neural regulation of immunity.…”

“…In their review published in Biological Signals and Receptors Castrilló n et al [50] examined the acute (after 18 h) and chronic effects of superior cervical ganglionectomy (after 12 days) on in vitro mitogenic responses of lymphocytes from submaxillary lymph nodes. At the two time intervals studied, essentially different phenomena were taking place in the vicinity of sympathetic varicosities, namely, a transient hyperactivity of the denervated organ as a consequence of the supraliminal transmitter release from degenerating varicosities 18 h after ganglionectomy, and an irreversible postsynaptic paralysis after 12 days of operation.…”

Interferon-Gamma Release in Sympathetically Denervated Rat Submaxillary Lymph Nodes

“…Our present results on IFN-Á release can partly explain those observations since an augmentation of IFN-Á release by cells derived from acutely denervated lymph nodes was found. However, the inhibition of IFN-Á release detected in cells derived from chronically sympathectomized lymph nodes did not correlate with the unhampered effect of Con A or LPS reported earlier [23]. Apparently, the reduced amounts of IFN-Á found in lymph nodes from chronic SCGx rats are enough to elicit a normal response to mitogens.…”

“…In a previous study we examined the acute (after 18 h) and the chronic effects of SCGx (after 12 days) on the in vitro mitogenic responses of lymphocytes from submaxillary lymph nodes [23]. In acutely denervated rats, LPS or Con A produced an increased mitotic response as compared to the innervated lymph nodes, whereas in chronic IFN-Á Release in Sympathetically Denervated Rat Submaxillary Lymph Nodes Neuroimmunomodulation 2000; 8:197-202 201 SCGx rats, the mitogen effect remained unchanged.…”