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Biomedical subjects

P Alm

Publications and source records attributed to P Alm.

At least 199 records · Page 11Linked to original sources
PubMed1978

Cholinergic innervation of the human urethra and urinary bladder: a histochemical study and review of methodology.

The present work gives a survey of the various methods for the histochemical demonstration of cholinergic nervous structures. The theoretical background and the specificity and sensitivity of the various methods are compared. It is concluded that the histochemical localization of the cholinergic transmitter metabolizing enzyme acetylcholine esterase still probably is the best method, giving a fairly good reflection of the distribution of cholinergic nerves. In comparison with the Falck and Hillarp technique for the demonstration of adrenergic nerves this method is much less specific and sensitive. The present work describes a rich supply of cholinergic nerves in the human urethra and urinary bladder in comparison with the scanty adrenergic innervation. Various functional aspects of the cholinergic innervation are discussed.

Acetylcholinesterase↗
PubMed1978

Regional changes in structural and functional integrity of myometrial adrenergic nerves in pregnant guinea-pig, and their relationship to the localization of the conceptus.

Pregnancy is accompanied by a reduction in uterine noradrenaline, and the study was undertaken to investigate associated structural and functional integrity of the sympathetic nerves in the organ. The formaldehyde-induced fluorescence of adrenergic nerves was studied in different uterine regions before and after in vitro incubation or injection with alpha-methyl-noradrenaline in pregnant and puerperal guinea-pig uterus at 6 time periods, from early pregnancy (about 20 days post coitum) to 3 months post partum. The changes were related to the position of the fetuses, which were often present in only one of the two uterine horns. There was a drastic loss of fluorescent adrenergic nerves in myometrial tissue from horns distended by fetuses. Attempts to restore this fluorescence by incubation or injection with alpha-methyl-noradrenaline were essentially ineffective. Tissues from uterine regions outside (and not distended by) fetuses (in the case of early pregnancy), from horns devoid of fetuses (in the case of unilateral pregnancy), and from the cervix also lost their noradrenaline-fluorescent nerves, but this occurred at a much later stage of pregnancy. After treatment with alpha-methyl-noradrenaline, a fluorescent plexus of sympathetic nerves could be restored to a considerable extent in these latter tissues. In puerperal animals the horn that had been devoid of fetuses regained its endogenous fluorescence much faster, and the uptake of alpha-methyl-noradrenaline was more efficient, than in the horn which had contained fetuses. In this latter horn clear signs of restoration of endogenous adrenergic fluorescence and a clear uptake capacity was not found until 3 months after delivery. In the tubal end of the uterus, the reduction in the number of fluorescent nerves was only insignificant, and the region thus clearly differed from the rest of the uterus. It is concluded that (1) there are clear regional differences with regard to the disappearance of the noradrenaline transmitter in the uterus, (2) this disappearance in early pregnancy is related to the position of the conceptus, and (3) the changes involve de- and regenerative phenomena as well as alterations in transmitter levels of intact neurons.

Adrenergic Fibers↗
PubMed1978

Differential effect on the sympathetic transmitter level in uterus and other organs of guinea-pig by drugs interfering with adrenergic nerve functions.

5 types of adrenergic blocking agents with different modes of action were administered and the rate of transmitter depletion was studied in different uterine regions of guinea-pig, and compared with that in the heart and submandibular gland by a combination of fluorescence histochemical and spectrofluorimetric methods. The tyrosine-hydroxylase inhibitor, H 44/68, as well as reserpine and guanethidine, produced a more efficient reduction in neuronal noradrenaline in the heart and submandibular gland than in the uterus. A differential action on the sympathetic transmitter, though less clearcut, was seen with 6-hydroxydopamine. The noradrenaline-depleting effect of metaraminol did not distinguish between those adrenergic nerves supplying the uterus from those of the control tissues. It is suggested that the differential effects may be related to a lower activity in the uterine adrenergic nerve system, probably because this system is to a large extent composed of short adrenergic neurons, which appear to have a particularly slow transmitter turnover.

Animals↗
PubMed1978

Cyclic and steroid-induced changes in adrenergic neurotransmitter level of guinea-pig uterus.

The uterine neurotransmitter, noradren,line, was examined histochemically and fluorometrically in guinea-pigs during the estrous cycle and after pretreatment with sex steroids. In diestrous animals noradrenaline values were higher than in the estrous state. Treatment with estradiol or progesterone alone did not markedly influence the level of uterine adrenergic transmitter, whereas combined estradiol and progesterone administration caused a clear-cut reduction in uterine noradrenaline. The quantitative changes in transmitter level did not reflect the marked alterations in weight during the various experimental conditions, and even inverse noradrenaline-weight relationships were observed. The findings offer further support for the concept of a steroid-mediated influence on uterine neurotransmission, where the uterine adrenergic nerves constitute a separate target for endocrine control, distinct from the rest of the uterus.

Adrenergic Fibers↗
PubMed1977

Adrenergic and Cholinergic Nerves of the Human Urethra and Urinary Bladder. A histochemical study.

The occurrence and distribution of adrenergic and acetylcholine esterase (AChE) positive nerves in the human urethra and urinary bladder were studied histochemically with the fluorescence method of Falck and Hillarp, and the copper thiocholine method of Koelle and Friedenwald. Both types of nerves were mainly confined to the layers of smooth muscle cells in the walls of the organs. In all parts of the urethra, there was a scanty supply of adrenergic nerves. Few adrenergic nerves were also found in the urinary bladder, except in the trigone area, where they were abundant. AChE-positive nerves were uniformly and richly distributed in the urinary bladder. Throughout the urethra the distribution of AChE-positive nerve fibres was uniform, but the number was clearly less than in the urinary bladder. No intrmurally located adrenergic or AChE-Positive ganglion cells could be demonstrated.

Acetylcholinesterase↗
PubMed1977

Regional distribution of autonomic nerves in guinea pig uterus.

Uterine adrenergic and cholinergic nerves were examined histochemically and chemically in combination with surgical denervation. There was a clear regional variation with a greater number of axon terminals in the tubal end of the uterine horn and in the cervix compared to the remainder (major part) of the uterine horn. No cholinergic nerves were found in the uterus but were abundant around the uterine artery and its primary ramifications. Clusters of ganglion cells were located near the cervix: the majority were acetylcholinesterase positive, whereas the remainder stored catecholamines. Unexpectedly, the suspensory ligament (connecting the tubal end of the uterine horn with the two lower ribs) was found to contain an extensive number of adrenergic nerves. The major part of the uterine horns, as well as the cervix, was innervated mainly from two sources contributing almost equally: the paracervical ganglia (short adrenergic neurons) and postganglionic fibers running in the hypogastric nerves. A restricted area at the tubal end of the uterus received most of its via the suspensory ligament.

Acetylcholinesterase↗
PubMed1977

Functional role of an adrenergic sphincter in the female urethra of the guinea-pig.

By means of a microtransducer catheter, the urethral pressure profile was recorded in female guinea-pigs. The maximum urethral pressure averaged 24 mmHg (range 18-27 mmHg) and was found 4 to 7 mm from the vesico-urethral junction. Fluorescence microscopy of the urethra showed an irregular distribution of fluorescent nerve terminals in the most proximal part of the organ. In a distal direction, there was a continuous increase in the number of adrenergic nerves, with a maximum 4 to 6 mm from the internal meatus, corresponding to the maximum intraurethral pressure point. In this region, a dense plexus of nerves supplied thick muscle coats of smooth muscle having an outer circular and an inner longitudinal orientation. The findings suggest that a specific region of the female guinea-pig urethra may serve as an "internal sphincter".

Animals↗
PubMed1976

Uncharted cholinergic nerves in the rabbit parotid gland.

Cholinergic nerves are shown to be left in the rabbit parotid gland after avulsion of the auriculo-temporal nerve: a cholinesterase inhibitor injected through the duct caused secretion, thereby revealing leakage of acetylcholine from cholinergic nerve endings, and acetylcholinesterase positive nerves were found histochemically. The incomplete cholinergic denervation offers an explanation to the fact that some choline acetyltransferase activity remains in the 'denervated' glands.

Animals↗
PubMed1976

Uptake, localization and secretagogic action of some biogenic amines in the submandibular and pancreatic glands of the guinea pig.

The effects of noradrenaline, 5-hydroxytryptamine (5-HT) 5-hydroxyptophan (5-HTP), dopamine, L-DOPA and carbamylcholine on the secretion of amylase from guinea pig submandibular gland and pancreas were studied. Carbamylcholine stimulated both pancreatic and salivary gland amylase release, whereas the biogenic amines elicted amylase secretion only from the submandibular gland. L-DOPA and 5-HTP, the precursor amino acids of dopamine and 5-HT, were without effects. In both glands 5-HT and dopamine were accumlated to a greater extent than their precursor amino acids. The uptake of biogenic amines into acinar cells and their effects on amylase secretion are compared and dicussed in terms of receptor specificity.

5-Hydroxytryptophan↗
PubMed1975

Variations in the level of uterine norepinephrine during pregnancy in the guinea pig.

The uterine smooth musculature is innervated by short adrenergic neurons which are unique in that their transmitter content varies during pregnancy and under the influence of exogenous sex hormones. Uterine norepinephrine was measured fluorometrically at 25 stages throughout pregnancy in the guinea pig, which was chosen because one of the pregnant uterine horns often is devoid of fetuses and hence not subject to mechanical tension. During the initial 10 days of pregnancy, the total organ content of norepinephrine was almost doubled whether the horn contained conceptuses or not. In the horn with conceptuses, norepinephrine was subsequently reduced in the course of the remaining gestation time to reach near-zero levels at term (about 65 days post coitus). In the empty horn, the amine level was constantly elevated until the last two weeks, during which it fell to the same low values as in the contralateral horn. Cervical norepinephrine exhibited the same variations during pregnancy as the empty horn. It is suggested that the characteristic variations in uterine norepinephrine reflect a hormonal influence on the system of short adrenergic neurons, with the addition of mechanical factors in that horn containing fetuses.

Animals↗