Lars Malmberg

Effects of long-term treatment with estrogen and progesterone on in vitro muscle responses of the female rabbit urinary bladder and urethra to autonomic drugs and nerve stimulation

Ovariectomized virginal rabbits were treated with either estrogen or progesterone for 4 to 6 months. In vitro responses of muscle strips of the bladder and circular urethra were examined. Estrogen resulted in bladder contractions in response to noradrenaline and phenylephrine, whereas these agonists were without effect or evoked weak relaxations in castrated animals (and normals). Estrogen also caused a rightward shift of the frequency-contraction curve to nerve stimulation. Progesterone increased bladder sensitivity to contraction-evoking bethanechol. Contractile urethral responsiveness to bethanechol increased after both steroids. Urethral sensitivity to noradrenaline, evoking contraction, increased following estrogen. Further, estrogen abolished the marked relaxatory urethral response to nerve stimulation of castrated (and normal) rabbits and caused contraction only, which was abolished by a combination of alpha-adrenoceptor antagonists and scopolamine. When comparing the present results with those of other studies, it is evident that hormone-induced changes become manifest at an early stage. The present animal study gives support for the use of estrogen in the therapy of stress incontinence and, further, it provides no objections to the use of progesterone in combination with estrogen in this condition.

Desmopressin, as a "designer-drug," in the treatment of overactive bladder syndrome.

This study looked at whether oral desmopressin, by decreasing kidney urine production, would prolong bladder filling‐time thereby increasing the time to reach maximum capacity, thus reducing overactive bladder (OAB) symptoms, and providing an alternative method of treatment to OAB sufferers.

Beta 1-adrenoceptor mediated salivary gland enlargement in the rat.

In the rat, prolonged activation of β1-adrenoceptors causes a gain in salivary gland weight, whereas prolonged blockade of these receptors causes a reduction in weight.

Effects of drugs and electrical field stimulation on isolated muscle strips from rabbit pharyngoesophageal segment

Muscle activity of isolated muscle strips from the middle pharyngeal constrictor, the inferior pharyngeal constrictor, the cricopharyngeal muscle, and the cervical esophagus of the rabbit was studied in organ baths in response to drugs and electrical field stimulation. These muscles of the pharyngo-esophageal segment seem to lack an autonomic adrenergic and cholinergic innervation, as determined by responses to specific drugs. The nerve-evoked contractile responses of the two lower muscles of the segment were almost completely abolished by the curarelike drug gallamine, suggesting a somatic cholinergic nerve supply. However, in the two upper muscles, the major part of the response was resistant to gallamine, which suggests involvement of nonadrenergic, nonmuscarinic, nonnicotinic receptors in the transmission of nerve impulses in these muscles. These results suggest a differential innervation of the upper and lower pharyngeal muscles.

Neuropeptide-containing nerve fibers in the pharynx of the rabbit

The distribution of peptide-containing nerve fibers in the pharyngeal region of rabbits was studied by immunocytochemistry. Neuropeptide Y (NPY)-containing fibers were numerous around blood vessels and moderate in number among bundles of striated muscle fibers. A few NPY-containing fibers were seen around seromucous glands and beneath the epithelium. Nerve fibers containing vasoactive intestinal peptide (VIP) were numerous around seromucous glands and moderate in number around blood vessels, bundles of muscle, and in the subepithelial layer. A few nerve fibers containing substance P (SP) were seen around blood vessels, seromucous glands, among bundles of muscle, and in the subepithelial layer. Nerve fibers containing calcitonin gene-related peptide (CGRP) were numerous. They were distributed close to blood vessels, among bundles of muscle, in the subepithelial layer, and within the epithelium. A conspicuous finding was the occurrence of CGRP within motor end plates of striated muscle.