Long-term reproductive cycles in rams after pinealectomy or superior cervical ganglionectomy

Long-term cycles in diameter of the testes, colouration of the sexual skin and plasma concentrations of testosterone, FSH and prolactin were monitored in groups of pinealectomized (PINX), superior cervical ganglionectomized (SCGX), and control Soay rams living near Edinburgh (56 degrees N). In Exp. 1, PINX, SCGX and control rams were kept outside for 4 years, and well defined seasonal cycles in each of the reproductive parameters were evident in all 3 groups (e.g. testosterone cycle length assessed by sine-wave analysis: 12.08 +/- 0.17, 12.39 +/- 0.14 and 12.15 +/- 0.10 months for PINX, SCGX and control rams respectively). Qualitative differences, however, were apparent between the groups in the timing and amplitude of the reproductive cycle. The seasonal peak in reproductive function occurred from July to September in the PINX and SCGX rams, some 2 months earlier in the year than in controls, while the amplitude of the cycle was less marked in the PINX and SCGX rams. There were no significant differences between the experimental groups in the seasonal cycle in the plasma concentrations of prolactin. In Exp. 2, SCGX and control rams were kept indoors under an artificial environment with a 32-week light cycle and constant nutrition for 4 years. Compared to the controls, in which the reproductive changes were synchronized to the driving light cycle, the SCGX rams showed poorly defined reproductive cycles of lower amplitude and longer period (e.g. testosterone cycle length: 57.8 +/- 6.1 and 32.1 +/- 0.2 weeks for SCGX and control rams, respectively). There was evidence of a cycle in some of the reproductive parameters in the SCGX rams with a period close to 32 weeks during the second half of the study (e.g. testosterone cycle 32.4 +/- 0.8 weeks), which was taken to indicate social induction from the neighbouring control rams. In two further short-term experiments, SCGX rams showed a decline in testicular activity in response to receiving a restricted diet (60% of controls) and an increase in testosterone secretion in response to exposure to oestrous ewes. The overall results illustrate that PINX and SCGX rams can generate long-term synchronized cycles in pituitary and testicular activity. The animals are apparently unable to respond to changes in daylength due to the loss of the functional pineal gland but they remain competent to respond to other environmental cues such as changes in nutrition, temperature and social factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Histochemical correlates of cold-induced trans-synaptic induction in the rat superior cervical ganglion

Synopsis The effect of prolonged pre-ganglionic activity induced by exposure to cold (5°C) was studied in intact and decentralized superior cervical ganglia of rats. Intact and decentralized ganglia of rats kept at room temperature served as controls. catecholamines were demonstrated histochemically using the formaldehyde-induced fluorescence method. The intensity of the fluorescence of the nerve cell bodies was estimated both visually and photometrically.Decentralization in itself had no effect on the intensity of the cell bodies for up to 16 days. Exposure to cold had no effect on the decentralized ganglia but caused a marked increase in the fluorescence intensity of some nerve cells of the intact ganglia, indicating that the increased fluorescence was mediated by the pre-ganglionic nerves. The increase lasted for the whole 16-day-length of exposure to cold.It is suggested that the observed change in the fluorescence intensity reflects an increase of the enzymes tyrosine hydroxylase and dopamine--hydroxylase, and thus represents a histochemical correlate of trans-synaptic induction.Sigrid Jusélius Foundation Research Fellow in the Department of Anatomy, University of Helsinki, April–July 1973.     

Fine structural changes in the hamster pineal gland after blinding and superior cervical ganglionectomy

Pineal glands of male hamsters 8 weeks after removal of both eyes or both superior cervical ganglia and those of untreated animals were studied by electron microscopy. In the blinded hamsters the reproductive organs were remarkably involuted, whereas the pinealocytes enlarged and were characterized by a tremendous hypertrophy of the smooth-surfaced endoplasmic reticulum, in the mesh of which some dense cored vesicles were distributed. In constrast the pinealocytes of ganglionectomized hamsters atrophied and were noted by a large number of lysosomes and sparsity of the agranular reticulum, the testes being significantly larger than the controls. The findings were interpreted to be compatible with the view that the pineal capability of producing antigonadal substance is augmented by blinding and is suppressed by cervical ganglionectomy due to the impairment of normal functioning of the pineal by denervation. It is assumed that the degree of development of the smooth endoplasmic reticulum in the pinealocyte is parallel to, and reflects that of the pineal activity. Probably the membranous organelle is involved in the elaboration of the pineal antigonadal substance.     

Catecholamines in olfactory mucosa decline following superior cervical ganglionectomy

The catccholamine content of rat peripheral olfactory tissuehas been determined. Norepinephrine is – 2 nmol/g tissuewhile dopamirte is <5% of this value. Unilateral destructionof the superior cervical ganglion (but not the olfactory bulb)results in a major decrease in the catecholamine content inthe ipsilateral olfactory mucosa. This indicates that the olfactorymucosa receives noradrenergic input from this sympathetic ganglion.     

Induction and growth of mammary tumors after superior cervical ganglionectomy in sighted and blinded-anosmic rats

Female rats were subjected to superior cervical ganglionectomy (Gx), blinding and anosmia (BAs) or combined procedures (BAsGx). Onset and growth of dimethylbenz(a)anthracene (DBMA)-induced mammary tumors was studied in these animals and compared to tumorigenesis in intact control rats. Carcinostatic effects were present in all surgically altered animals, as evidenced by a trend toward reduced tumor incidence, reduced final tumor mass, and a significant reduction in mean number of tumors in Gx and BAsGx rats, and increased regression of tumors in BAs rats compared to intact group. Reduced tumorigenesis was paralleled by a trend toward either an increase (BAs) or a decrease (Gx and BAsGx) in the activity of pineal hydroxyindole-O-methyltransferase (HIOMT) compared to intact group. In addition, BAs and BAsGx animals showed a significant reduction in body weight. These results suggest that Gx reduces mammary tumorigenesis in both sighted and BAs rats. They further confirm the findings of others on reduced mammary tumorigenesis in BAs rats. Possible involvement of multiple carcinostatic mechanisms in different animal models is discussed.     

Effect of bilateral superior cervical ganglionectomy (SCG) on pituitary adrenal function in the male albino rat.

The effect of sympathetic denervation (bilateral superior cervical ganglionectomy) on several aspects of pituitary adrenal function was studied in 250-300g rats. Group I=Sham-op, Group II=superior cervical ganglionectomy. (1) There was no significant difference between these groups in the plasma corticosterone (B) response to ether or immobilization stress or to ACTH administration. (2) Circadian periodicity of plasma B was determined by sequential (q.4h) tail vein sampling under LD (lights on 0800) off 2000) and under DL (lights on 2000, off 0800). Both groups showed similar peak and trough concentrations. Phase shifting occurred in both groups at day 11. (3) Compensatory adrenal hypertrophy of similar magnitude was present in both groups 10 days following unilateral adrenalectomy. These studies indicate that sympathetic input from the superior cervical ganglia is not involved in stress induced, circadian or some feedback aspects of pituitary adrenal function.     

Effect of superior cervical ganglionectomy on Harder (rat and rabbit) and Loewenthal (rat) glands]

An unilateral superior gangliectomy induce morphological changes in the way of an hypersecretory activity of the harderian gland. If the unmyelinised nervous system is not notably affected, some specific cytological aspects are undoubted. (In rats as in rabbits). On "harderised" spots in the outer orbital glands of rats, the same changes occur in the same delay (27 to 130 days).     

The role of adrenoreceptors in the regulation of oxytocin and vasopressin release after superior cervical ganglionectomy.

In male rats under anaesthesia, dialysis of the venous blood from sella turcica region was carried out. Vasopressin and oxytocin content was determined in the dialysates by radioimmunoassay. The obtained results indicate that: 1. Electrical stimulation of the superior cervical ganglion causes an increase in vasopressin and oxytocin release. 2. 20 days after superior cervical ganglionectomy the vasopressin and oxytocin release increased. 3. Superior cervical ganglionectomy immediately before the dialysis evoked a several times increase in vasopressin and oxytocin release. 4. Application of alpha1-blocker, prazosin, as well beta-blocker, propranolol, has partially prevented the increase in vasopressin release which was found immediately after superior cervical ganglionectomy. 5. Contrary to vasopressin, the increase in oxytocin release after superior cervical ganglionectomy is completely prevented by the beta-blocker, propranolol, and only partially by the alpha1-blocker, prazosin.     

Ultrastructural changes in the nerves innervating the cerebral artery after sympathectomy

Summary The ultrastructure of the innervation of the anterior cerebral artery of the rat was studied in control animals and in animals after superior cervical ganglionectomy.Fluorescence histochemistry shows a periarterial network of intensely fluorescent fibers which are divided into two groups, adventitial and periadventitial. The fluorescence begins to decrease 26 hours after, and completely disappears about 32 hours after, ganglionectomy.Fine structural changes are first observed 18 hours after ganglionectomy, when the axoplasm of degenerating axons becomes electron dense. This density gradually increases up to about 32 hours. By 32 hours most axons with disintegrating axolemmas become inclusion bodies of the Schwann cells. At this stage, synaptic vesicles can still be distinguished as less dense areas, but the membrane structures of synaptic vesicles and mitochondria are difficult to recognize. The degenerating axons are gradually absorbed and by 38 hours dense, residual bodies are observed in the Schwann cells. Generally speaking, the degeneration occurs first in the adventitial fibers and then in the periadventitial fibers. The transient appearance of small, granular vesicles is noticed in axon terminals about 18 hours after denervation, although very few small, granular vesicles are seen in control tissue or at later stages of degeneration.     

Alteration of seasonal reproductive patterns in mares following superior cervical ganglionectomy.

Oestrous behaviour, ovarian follicular development, ovulation and changes in hair coat were observed in Pony mares which were unoperated, sham-ganglionectomized control or bilaterally superior cervical ganglionectomized. Surgery was performed during the winter anoestrus (1975--1976). Reproductive patterns in all groups were similar during the first breeding season (1976) after operation but in ganglionectomized mares the onset of the next breeding season (date of first ovulation in 1977), the pattern of follicular development, date of first oestrus and pattern of hair coat changes were all significantly delayed relative to those of the non-operated and sham-operated mares in 1976 and 1977 and relative to their own patterns in 1976. These results indicate that the pineal-hypothalamo-pituitary axis may regulate or moderate annual reproductive rhythms in mares.     

Ipsilateral thyroid growth and depressed thyroid hormone synthesis and content after unilateral superior cervical ganglionectomy in rats

The role of the sympathetic nervous system in the control of the goitrogenic response was examined in adult male rats subjected to unilateral superior cervical ganglionectomy 12-30 days earlier. A spontaneous goiter as well as an increased thyroid growth after the administration of the goitrogenic agents methylmercaptoimidazole and thyrotropic stimulating hormone (TSH) were found in the ipsilateral lobe. Norepinephrine and epinephrine content decreased significantly by 80 and 31%, and thyroxine (T4) and triiodothyronine (T3) content by 24 and 15%, in the ipsilateral lobe. After the injection of a tracer dose of 125I, percent radioactivity incorporation to diiodotyrosine (DIT) was higher, and that to monoiodotyrosine (MIT) lower, in the ipsilateral lobe; additionally a lower ratio "labeled T3 + T4/labeled DIT" was found in the denervated thyroid lobe. These results suggest that the sympathetic nerve terminals in the thyroid gland modulate the organ's response to circulating TSH.     

Immunocytochemical and circadian biochemical analysis of neuroactive amino acids in the pineal gland of the rat: effect of superior cervical ganglionectomy

Summary Semiquantitative immunocytochemistry by immuno-gold techniques revealed differences in the spatial distribution of glutamate, glutamine, and taurine within the pineal gland, with greatest labeling over pinealocytes, glia, and endothelia, respectively. At the subcellular level, glutamate labeling tended to be highest over pinealocyte synaptic ribbons and mitochondria, and lowest over lipid inclusions. Pineal levels of glutamate, glutamine and taurine, as measured by high performance liquid chromatography, did not vary over a light: dark cycle. Superior cervical sympathetic denervation, which abolishes pineal melatonin synthesis, resulted in a nearly 50% reduction in pineal glutamate levels, but had no effect on levels of glutamine and taurine. Other amino acids (alanine, arginine, aspartate, serine) were reduced by 23%–33% following sympathectomy. These data suggest an important role for glutamate in pinealocyte function(s) possibly related to the noradrenergic innervation of the gland.     

Histochemical studies on carbohydrate metabolism in rat liver after galactosamine administration.

The development of hepatitis, induced in 48 rats by the administration of galactosamine (GalN) in varying doses, was studied with the use of substrate and enzyme histochemical techniques. The so-called atypical glycogen, which is at first highly resistant to diastase, was shown to be digestible after deamination. The increasing accumulation of atypical glycogen during the course of GalN-hepatitis conceals the loss of normal glycogen when the PAS-reaction is used. Nevertheless glycogenolysis could also be demonstrated by the increasing activity of phosphorylase. The acid phosphatase activity was progressively diminished, which was interpreted as signifying early lysosomal damage. G6Pase activity remained nearly constant but SDH showed a decrease in activity after 12 h. These histochemical results are considered to provide deeper insight into the pathological mechanism of GalN-hepatitis.