Uterine adrenergic and cholinesterase-positive nerves and myometrial catecholamine concentrations during pregnancy in sheep

Noradrenergic and cholinergic nerves in the uterus of the Japanese long-fingered bat, Miniopterus schreibersii fuliginosus, change with reproductive cycle

The pattern of uterine innervation by noradrenergic (NA) and acetylcholinesterase-positive (AChE) nerves in different reproductive stages of the adult Japanese long-fingered bats were investigated histochemically and immunohistochemically. In the non-pregnant bat, the uterine horn was supplied with abundant NA and AChE nerves. These two types of nerves were closely associated with the uterine arteries and myometrial smooth muscles. In the pregnant bat, NA and AChE nerves supplying the uterus did not degenerate much during hibernating period, but reduced markedly after arousal. In the postpartum bat, the density of nerves recovered progressively. The significant change in the innervation pattern of uterine NA and AChE nerves in the pregnant bats under and after hibernation, and in the postpartum bat must be considered in relation to the adrenergic and cholinergic controlling mechanisms on the uterine function that is matched for the unique reproductive cycle of this bat.

The bovine tubouterine junction: general innervation pattern and distribution of adrenergic, cholinergic, and peptidergic nerve fibers

The innervation of the bovine tubouterine junction was studied in sexually mature heifers using antisera against various neuronal markers and a modified acetylcholinesterase method. The vast majority of the nerve fibres in the bovine tubouterine junction belongs to the sympathetic nervous system; peptidergic and cholinergic fibers are restricted to characteristic locations. The endosalpinx in the adovarian portion of the terminal tubal segment is poorly innervated. The mucosa of the aduterine portion and of the tubouterine transitional region proper receives a strikingly dense innervation, which is observed mainly in combination with a strong vascularisation of specialised mucosal structures. In the endometrium, perivascular nerves accompany the ascending spiral arteries but sporadic contacts between nerve fibres and uterine glands are also observed. From the muscular coat the inner longitudinal layer of the terminal tubal segment is more richly supplied by nerve fibres than the intermediate circular and outer longitudinal layers of the tubouterine junction. No changes in the innervation pattern were seen during the different stages of the sexual cycle.

Noradrenergic and acetylcholinesterase-positive nerve fibres of the uterus in sexually immature and cycling rats

The distribution and density of the noradrenergic and acetylcholinesterase-positive nerve fibres were histochemically studied in different uterine regions of prepubertal and cycling rats in dioestrus and oestrus. Besides the rich and double innervation of blood vessels, both types of nerve fibre were found in the myometrium and cervical musculature. The non-vascular noradrenergic network looked denser at the tubal end of the horns and at the cervix, whereas the acetylcholinesterase-positive innervation was poor at the tubal end, increasing toward the cervix. Contrasting with the middle third of the uterine horn, at the tubal end, the myometrial longitudinal layer was much more innervated than the circular one, especially by the noradrenergic nerve fibres. The prepubertal rats presented an adult pattern of uterine autonomic innervation. In the cycling animals, this innervation was nearly the same during oestrus and dioestrus regarding both the density of nerve fibres and intensity of the histochemical reactions.

Differential control of placental lactogen release and progesterone production by ovine placental tissue in vitro

The hypothesis that placental secretion of progesterone (P4) and ovine placental lactogen (oPL) are controlled through different mechanisms was tested. Placental tissue was obtained at days 133-138 of pregnancy, and explant incubations were established using 200 mg tissue per flask in 5 ml O2-saturated DMEM containing 24 mM HEPES and lacking phenol red (pH 7.4). Following a 30-min preincubation, and a 15-min control period, test substances were added and incubations continued, with periodic gassing, for 4 h at 37 degrees C in a shaking water bath. Dopamine (DA), norepinephrine (NE) and epinephrine significantly stimulated P4 production (P less than 0.05). The enhancement of placental P4 production was mimicked by the addition of 8-bromo-cyclic adenosine monophosphate and forskolin (P less than 0.05). The response to catecholamines was abolished by the addition of propranolol (P less than 0.05) but not by phentolamine (P greater than 0.05). Inclusion of a membrane-permeant substrate for P4 synthesis, 25-hydroxycholesterol, increased basal (P less than 0.05) but did not enhance agonist-induced P4 production (P greater than 0.05). High performance liquid chromatographic analysis of placental tissue demonstrated the presence of DA (80.8 +/- 7.07 pg/mg) and NE (48.8 +/- 5.77 pg/mg), as well as catecholamine metabolites. Addition of 1,2-dioctanoyl-sn-glycerol (DAG) or phorbol 12-myristate-13-acetate (PMA) enhanced oPL secretion (P less than 0.05) without affecting P4 production. The response to DAG and PMA, representing the release of considerably more oPL than can be detected by extracting the tissue, was not influenced by treatment with cycloheximide (P greater than 0.05) indicating that secretion of preformed oPL is regulated by the protein kinase C pathway. These results support the hypothesis that the secretion of oPL and the production of P4 are controlled by different mechanisms.