Chemical sympathectomy-induced changes in TH-, VIP-, and CGRP-immunoreactive fibers in the rat mandible periosteum: influence on bone resorption.

The expression of neurotransmitter receptors by bone cells supports the concept that the nervous system is a regulator of bone metabolism. The discrimination of the respective roles of the sensory and sympathetic nervous systems requires evidence of topographic relationships between the corresponding fibers and the cells involved in bone turnover, in vivo. In this study, the influence of the sympathetic system on bone resorption was assessed by using a synchronized model of cortical resorption along the mandible.

Spatial segregation within the sacral parasympathetic nucleus of neurons innervating the bladder or the penis of the rat as revealed by three-dimensional reconstruction.

The purpose of the present investigations was (1) to examine the spatial organization of preganglionic neurons of the sacral parasympathetic nucleus in the lumbosacral spinal cord of male adult rats and (2) to search, in this nucleus, for a possible segregation of sub-populations of neurons innervating the penis or the bladder, respectively. To estimate their spatial organization, neurons of the sacral parasympathetic nucleus were retrogradely labeled by wheat germ agglutinin coupled to horseradish peroxidase applied to the central end of the sectioned pelvic nerve. The sub-populations of lumbosacral neurons innervating the corpus cavernosum of the penis or the dome of the bladder were identified using transsynaptic retrograde labeling by pseudorabies virus injected into these organs in different rats.

Endothelial and neuronal nitric oxide synthases are present in the suprachiasmatic nuclei of Syrian hamsters and rats.

Nitric oxide (NO) is involved in the transmission of light information to suprachiasmatic nuclei (SCN). By immunocytochemistry, we showed that both neuronal and endothelial NO synthase isoforms (nNOS and eNOS) were present in the SCN of rats and hamsters. nNOS-immunoreactive neurons were located mainly around the SCN with only a few nNOS neurons within the nucleus.

Relaxant effect of the calcitonin gene-related peptide (CGRP) on the nonpregnant and pregnant rat uterus. Comparison with vascular tissue.

To explore the role of calcitonin gene-related peptide (CGRP) in rat pregnancy, we determined the density of myometrial CGRP-encoded nerve fibre terminals and examined, in an organ bath, the relaxant effect of the peptide on uterine strips near parturition. Comparisons were made with the uterus and aorta of nonpregnant rats. In the myometrium, CGRP immunoreactive nerve fibers were abundant in nonpregnant rats and scarce at the parturient stage.

Androgens modulate nitric oxide synthase messenger ribonucleic acid expression in neurons of the major pelvic ganglion in the rat.

Expression and androgen regulation of the gene for neuronal nitric oxide synthase (NOS I) were examined in neurons of the major pelvic ganglia in male rats. Some of these postganglionic neurons innervate the penis and produce nitric oxide, which is believed to play a major role in penile erection. Rats were either castrated or sham operated and implanted with SILASTIC brand capsules filled with powdered testosterone (T) or 5alpha-dihydrotestosterone (5alphaDHT) or left empty.

Localization of androgen receptor in nitric oxide synthase- and vasoactive intestinal peptide-containing neurons of the major pelvic ganglion innervating the rat penis.

Neurons of the rat major pelvic ganglia provide innervation to the pelvic organs and external genitalia. In these ganglia, a subpopulation of neurons containing either nitric oxide synthase or vasoactive intestinal peptide or both molecules, is involved in penile erection. The androgen dependence of penile erection is a well established fact.

Opposite effects of nitric oxide on identified inhibitory and excitatory cholinergic synapses of Aplysia californica.

The effects of nitric oxide on evoked acetylcholine (ACh) release were studied at two identified cholinergic neuro-neuronal synapses of the nervous system of the mollusc Aplysia californica. The NO-donor, 3-morpholinosydnonimine (SIN-1), decreased the amplitude of evoked inhibitory postsynaptic currents (buccal ganglion) and potentiated that of evoked excitatory postsynaptic currents (abdominal ganglion). SIN-1 acted by modulating the number of ACh quanta released.

A nitric oxide synthase activity is involved in the modulation of acetylcholine release in Aplysia ganglion neurons: a histological, voltammetric and electrophysiological study.

The role of nitric oxide or related molecules as neuromodulators was investigated in the buccal and the abdominal ganglia of the mollusc Aplysia californica. In a first step we showed that reduced nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry and specific nitric oxide synthase immunohistochemistry labelled the same neurons and fibres in both ganglia, pointing to the presence of a neuronal nitric oxide synthase. In a second step, we performed voltammetric detection of nitric oxide-related molecules using a microcarbon electrode in a reduction mode.

A large proportion of pelvic neurons innervating the corpora cavernosa of the rat penis exhibit NADPH-diaphorase activity.

Nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry, which indicates the presence of neural nitric oxide synthase, the enzyme responsible for the generation of nitric oxide, was used in combination with retrograde labelling methods to determine, in whole-mounts and sections of rat major pelvic ganglia, whether neurons destined for the penile corpora cavernosa were able to produce nitric oxide. In whole-mount preparations of pelvic ganglia, among the 607 +/- 106 retrogradely labelled neurons innervating the penile corpora cavernosa, 84 +/- 7% were NADPH-diaphorase-positive, 30 +/- 7% of which were intensely histochemically stained. In serial sections of pelvic ganglia, out of a mean count of 451 retrogradely labelled neurons, 65% stained positively for NADPH-diaphorase.

Autonomic control of penile erection: modulation by testosterone in the rat.

The role of testosterone on peripheral autonomic control of penile erection was studied in rats. Erectile response to cavernous nerve stimulation was measured by intracavernous pressure associated with arterial blood pressure monitoring in anesthetized adult males. Comparison was performed between control (Co), castrated (Ox) and castrated, testosterone-replaced (OxT) rats.

Resumption of gonadotrophin release during the post-partum period in suckling and non-suckling ewes.

The post-partum secretion of LH, FSH and prolactin was monitored in 15 suckling and 6 non-suckling Préalpes du Sud ewes lambing during the breeding season by measuring plasma hormone concentrations daily at 6-h intervals and also weekly at 20-min intervals for 6 h from parturition to resumption of regular cyclic ovarian activity. There was a constant phenomenon in the resumption of normal patterns of FSH and LH secretion: there was a rise in FSH values culminating on average on Day 4 post partum and returning subsequently to values observed during the oestrous cycle, and concurrently an increase in the frequency and amplitude of LH pulses more progressive in suckling than in non-suckling ewes which led to an elevation of LH mean concentrations and occurrence of an LH surge. Since neither the FSH secretory pattern nor FSH mean values differed between suckling and non-suckling ewes, the results suggested that LH pulsatile pattern was a major limiting factor for the resumption of normal oestrous cycles.

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes.

In Préalpes de Sud ewes after an autumn lambing, the mean post-partum interval to first LH surge was 10 +/- 1 days and 17 +/- 1 days for non-suckling and suckling ewes, respectively. Post-partum interval to first luteal phase, estimated from plasma progesterone concentrations, was similar in non-suckling and suckling ewes (27 +/- 1 days and 28 +/- 5 days, respectively). Interval to first oestrus was shorter in non-suckling (22 +/- 2 days) than in suckling ewes (35 +/- 2 days) but these first oestrous periods were followed by short luteal phases in 60% (12/20) of non-suckling ewes and in only 7% (2/29) of suckling ewes.

Interactions between 17 beta-estradiol and the hypothalamo-pituitary beta-endorphin system in the regulation of the cyclic LH secretion.

This paper further substantiates the physiological role of beta-endorphin (beta-END) in the control of the cyclic LH secretion and provides new data on the interactions between 17 beta-estradiol (17 beta-E2) and beta-END at both the hypothalamic and pituitary levels. At the hypothalamic level, during the estrous cycle in rats, beta-END concentrations were highest on diestrus I in the arcuate nucleus, median preoptic area and median eminence and lowest at the time of the preovulatory 17 beta-E2 surge on proestrus, before the subsequent preovulatory hypothalamic GnRH and plasma LH surges. Data obtained in ovariectomized 17 beta-E2-treated ewes support the direct involvement of 17 beta-E2 in changes in beta-END and GnRH concentrations in these hypothalamic areas.

Diurnal variation in the response of anoestrous ewes to the ram effect.

The re-introduction of rams after a period of separation was used to stimulate LH secretion and induce ovulation in seasonally anovulatory ewes maintained under natural photoperiod. In 2 experiments, the rams were introduced in the morning or the evening to test for diurnal variations in responsiveness to the treatment. In the first experiment, with Romanov ewes, the ram-induced increase in tonic LH secretion was significantly earlier in the ewes treated (N = 6) at 07:30 h (mean +/- s.

Differential patterns in luteal prolactin and LH receptors during pregnancy in sows and ewes.

In the sow, a dramatic increase of LH specific binding was observed during the second half of pregnancy. This was due to an increase in receptor number (41 fmol and 95 fmol/mg protein at Days 50 and 105 respectively). The apparent association constant was unchanged.

Circulating angiotensin II and adrenal receptors after nephrectomy.

Mineralocorticoid secretion is predominantly controlled by the octapeptide angiotensin II, which exerts trophic actions on the adrenal glomerulosa and acute regulatory effects on aldosterone biosynthesis. The trophic actions include stimulation of angiotensin II receptors and enzymes of the aldosterone biosynthetic pathway, with corresponding enhancement of the aldosterone secretory capacity of the adrenal gland. The positive regulatory action of angiotensin II on its adrenal receptors occurs with elevations of the circulating peptide concentration within the physiological range and probably contributes to the increased sensitivity of the adrenal during sodium deficiency.

High prekallikrein levels during pregnancy.

Prekallikrein levels are significantly increased during pregnancy. The increase is neither due to an excess of Hageman factor or of an activator, nor to the decrease of an inhibitor.

Amniotic fluid phospholipids and fatty acids in normal pregnancies. Relation to gestational age and neonatal condition.

The plamitic acid/stearic acid ratio (P/S) follows such a rise during weeks 35 and 36 that it can be considered as a valuable index of gestational age.