Effects Of Neonatal Capsaicin Treatment Research Articles

Effect of neonatal capsaicin treatment on cholecystokinin-(CCK8) satiety and axonal transport of CCK binding sites in the rat vagus nerve

Cholecystokinin (CCK) binding sites which accumulate at ligatures placed on the rat vagus nerve may mediate the satiety actions of CCK. Treatment of neonatal rats with capsaicin attenuated the satiety effect of injected CCK in adult life. Capsaicin pretreatment also reduced, but did not eliminate, the accumulation of CCK binding sites proximal and distal to ligatures on either cervical trunk. A similar effect was observed following ligation of subdiaphragmatic vagal trunks. The CCK receptor antagonists, MK-329 and L-365,260, inhibited binding to capsaicin- and vehicle-treated nerves to a similar degree. Densities of CCK binding sites in the nucleus tractus solitarius and area postrema were also markedly affected by neonatal capsaicin treatment.

Neonatally administered capsaicin induces functional disturbances in the carotid afferent pathway to the nucleus tractus solitarius.

The effect of neonatal capsaicin treatment on chemo- and/or barosensory input to the medulla was studied in 35-40-day-old rats. By means of responses evoked in the nucleus tractus solitarius by stimulating the ipsilateral sinusal nerve, the excitability of slow-conducting carotid afferent fibers and the effect of substance P microinjection into the fourth ventricle were evaluated. Neonatal capsaicin resulted in reduced amplitude of the late component of the evoked responses, increased chronaxie values in the strength-duration paradigm, and increased sensitivity of evoked responses to the inhibitory effect of intracerebroventricular administered substance P. The results indicate that capsaicin given early in life leads to functional disturbances of chemo- and/or barosensory input to the nucleus tractus solitarius, involving both the slow-conducting primary afferents and the receptors for substance P of the second-order cells of the sensory pathway.

Effects of neonatal capsaicin treatment and streptozotocin-induced diabetes on urinary bladder function in rats

A significant increase in the size and weight of the urinary bladder was observed 2 weeks after streptozotocin treatment and 2 months after neonatal capsaicin treatment. Both treatments induced a significant increase in the level of [ 3H]quinuclidinyl benzilate binding to muscarinic cholinergic receptors in the urinary bladder membranes. However, contractile responses of urinary bladder muscle strips to carbachol (0.3–20 μM) were not significantly affected by either treatment. On the other hand, neonatal capsaicin treatment, but not streptozotocin treatment, significantly enhanced contractile responses of bladder strips to electric field stimulation.

The effects of neonatal capsaicin treatment on the sensory innervation of the nipple and on the milk ejection reflex in the rat.

Much of the sensory innervation of the nipple is provided by fibers of small calibre (A delta and C). In order to determine the contribution of unmyelinated C-fibers to this innervation and to the physiology of lactation, mammary afferents were studied in rats that had succeeded in lactating after neonatal treatment with capsaicin, a neurotoxin which selectively destroys C-fibers. After subcutaneous injection of horseradish peroxidase-wheat germ agglutinin (HRP-WGA) into the nipple of capsaicin-treated lactating rats, cell counts and surface area estimates of peroxidase-labelled and unlabelled cells were made in the corresponding dorsal root ganglia (DRG) and compared to values obtained in untreated lactating females that had received similar tracer injections. The segmental distribution of HRP-labelled primary sensory neurons in the capsaicin-treated rats was similar to that in untreated controls, but the number of labelled cells was significantly reduced at each segmental level. This reduction reflected a marked decrease in C-fibers, since there was a striking reduction in the number of small HRP-labelled and unlabelled cell bodies in the DRG and unmyelinated fibers in the dorsal roots. Peroxidase labelling within the dorsal horn of capsaicin-treated rats was also substantially diminished. About 40% of the females that had been treated neonatally with capsaicin gave birth and lactated. Although the average weight gain of their litters was retarded with respect to that of litters of untreated controls, the milk ejection reflex appeared to function normally.(ABSTRACT TRUNCATED AT 250 WORDS)

A quantitative study of the effects of neonatal capsaicin treatment and of subsequent peripheral nerve transection in the adult rat

The effects of unilateral intercostal nerve transection have been studied in adult rats neonatally treated with capsaicin. Two rats were treated with capsaicin-free vehicle and served as controls. It is shown that capsaicin treatment leads to a dorsal root ganglion cell loss of about 43%, and about a 72% loss of unmyelinated dorsal root fibers. Myelinated dorsal root fibers remain unaffected. The cell size spectrum shows a 27% increase in median cell area in the capsaicin-treated rats, indicating a loss of preferentially smaller cells. A subsequent peripheral nerve transection resulted in a further cell loss of about 30% with no major change in cell size spectrum. The peripheral nerve transection also somewhat further reduces both the number of unmyelinated and myelinated dorsal root axons. The data indicate that neurons which die after a prripheral nerve transection belong to both the groups of cells, which are capsaicin-sensitive and capsaicin-resistant.

The effects of neonatal capsaicin treatment on levels of substance P-, somatostatin- and vasoactive intestinal polypeptide-like immunoreactivities in the gastrointestinal tract of the rat

The effects of neonatal capsaicin treatment on levels of substance P-, somatostatin- and vasoactive intestinal polypeptide-like immunoreactivities in the gastrointestinal tract of the rat

Capsaicin-sensitive afferent vagal neurons innervating the rat liver

The effects of neonatal capsaicin treatment on the vagal afferent neurons innervating the liver have been studied in the rat. The smallest neurons (up to 180 μm 2) innervating the left and median lobes and the right and caudate lobes of the liver are completely destroyed by neonatal capsaicin administration and the number of neurons up to 300 μm 2 is reduced. It is suggested that the capsaicin-sensitive neurons in the nodose ganglion innervating the liver may be involved in nociception.

Regional distribution of a novel pituitary protein (7B2) in the rat spinal cord: Effect of neonatal capsaicin treatment and thoracic cord transection

Using a specific radioimmunoassay, a novel pituitary protein (7B2) was shown to be distributed throughout the rat spinal cord. The concentration of 7B2-like immunoreactivity (7B2-IR) was significantly higher in dorsal lumbar than in whole lumbar cord, and the highest level was found in the sacral region. On both gel and high-performance liquid chromatography, 7B2-IR in rat spinal cord eluted in the same position as 7B2-IR extracted from porcine pituitary gland. Neonatal capsaicin treatment did not change dorsal lumbar spinal cord 7B2-IR concentrations, suggesting that it is not predominantly present in unmyelinated primary afferent fibres. Thoracic cord transection, however, resulted in significant increases of 7B2-IR in lumbar and especially sacral regions, providing evidence of a 7B2-containing ascending pathway originating in the lumbosacral spinal cord.

Discussion on the session on neurochemistry of nociception: report by M. Goedert

The finding reported by Dr T. M. Jessell of the presence of certain glycolipid stage-specific embryonic antigens on subpopulations of rat dorsal root ganglion cells very probably represents a property of the sensory neuron and is not causally related to the presence of certain neuropeptides in these nerve cells. This is illustrated by the fact that, although all dorsal root ganglion cells containing somatostatin-like immunoreactivity express a glycolipid on their surface, this antigen is not found on central nervous system cells containing somatostatin-like immunoreactivity. In discussion it was suggested that it would be interesting to investigate the effects of neonatal capsaicin treatment on the presence of the glycolipid determinants.

Neonatal capsaicin treatment prevents insulin-stress-induced adrenal catecholamine secretion in vivo: Possible involvement of sensory nerves containing substance P

We have investigated the effects of neonatal capsaicin treatment on stress-induced catecholamine release from adult rats in vivo. Catecholamines released into the inferior vena cava following insulin injection were separated by HPLC and measured by electrochemical detection. Neonatal capsaicin treatment depleted the substance P levels in the splanchnic nerve of adult rats by 70% and prevented the insulin-induced hypoglycaemia from evoking release of adrenaline. The results of this study provide the first evidence in vivo for the neuromodulatory role of sensory nerves containing substance P in the secretion of catecholamines from the adrenal medulla.

The effects of neonatal capsaicin treatment on growth and subsequent reproductive function in the rat

The results of the present study describe the following effects of neonatal capsaicin treatment on growth and reproductive function in the rat. Neonatal capsaicin treatment in the rat resulted in a retardation of body growth through adulthood most pronounced at 35 days of age. Capsaicin-treated rats had normal estrous cycles, but mated significantly less frequently than age-matched controls. Confirmed matings in capsaicin-treated female rats resulted in significantly fewer pregnancies compared to controls. Male rats treated with capsaicin as neonates produced significantly fewer pregnancies when mated with untreated females compared to controls. Ovulation, sperm transport, and fertilization occur normally in capsaicin-treated rats. The decidual response was markedly diminished in mated capsaicin-treated rats. These findings led to the conclusion that the neurohormonal reflex, which is normally initiated through the stimulation of the cervix by copulation, and which ultimately stimulates secretion of pituitary luteotropic hormones, did not occur in capsaicin-treated rats. Thus, ovarian progesterone secretion was not facilitated resulting in inadequate hormonal support for implantation, pregnancy or pseudo-pregnancy. These data further suggest that the sensory limb of this neurohormonal reflex may consist of capsaicin-sensitive, possibly substance P containing, primary afferent fibers.

Effects of neonatal capsaicin treatment on thiamine monophosphatase (TMPase) activity in the substantia gelatinosa of the rat spinal cord

The present study investigated changes in gelatinosal TMPase activity following capsaicin treatment. The gelatinosal TMPase activity was positive around postnatal day 3, and the activity disappeared when newborn rats were treated with capsaicin on postnatal days 2 or 3. The absence of TMPase activity was still observed four months after treatment. The possibility that TMPase is associated with nociception has to be considered.

Effects of neonatal capsaicin treatment on nociceptive thresholds in the rat

The responsiveness to noxious thermal, mechanical, and chemical stimuli was examined in adult rats that had been treated neonatally with capsaicin. A range of capsaicin doses was employed to determine whether the neurotoxicity of capsaicin to primary afferent fibers would be manifested behaviorally in a selective effect on nociceptive thresholds to specific stimuli. Animals were given 5 to 100 mg/kg of capsaicin at 2 days of age and were examined 2 to 4 months later using the tail flick and hot plate tests to determine thermal thresholds, the paw pressure test to determine mechanical thresholds, and the formalin test to determine chemical thresholds. Significant impairments of treated animals' responses to all three types of stimuli were found at high doses of capsaicin and at doses which seem to lead to the depletion of only unmyelinated primary afferent fibers. Slightly higher doses of capsaicin were required to increase thermal nociceptive thresholds in the tail flick test as compared with the other tests, and mechanical nociception seemed to be the most sensitive to the effects of capsaicin. At any particular dose of capsaicin, considerable variability was found in the responsiveness of animals to noxious stimuli. This may partly explain the inconsistencies in studies of nociceptive thresholds in capsaicin-treated animals. The results also demonstrate the difficulty of correlating the degree of analgesia exhibited by these animals with the extent of loss of primary afferent fibers or with the depletion of afferent putative peptide transmitters.

Cholecystokinin in the rat spinal cord: distribution and lack of effect of neonatal capsaicin treatment and rhizotomy

The distribution of cholecystokinin (CCK) and gastrin-like immunoreactivities in rat spinal cord and spinal roots was studied with two sequence-specific radioimmunoassays. No gastrin was found in the cord or in spinal roots or sensory ganglia, however CCK was present at all levels of the cord and was concentrated in the dorsal horn. No CCK was found in sensory roots. Neonatal capsaicin treatment had no effect on ventral cord CCK and caused a small increase in dorsal cord levels. Neither dorsal rhizotomy nor combined dorsal and ventral rhizotomy affected CCK levels in either dorsal or ventral cord. These results indicate that most of the CCK in the rat spinal cord is not present in the terminals of primary afferent fibers.

The effects of neonatal capsaicin treatment on dorsal root afferents

The effects of neonatal capsaicin treatment on dorsal root afferents

Appearance of histochemically detectable ionic calcium in degenerating primary sensory neurons

The effect of neonatal capsaicin treatment on the fine structure and localization of ionic calcium in sensory ganglion cells has been investigated in rats. Neonatal capsaicin treatment resulted in the degeneration of certain type B sensory neurons. At the same time ionic calcium was demonstrated histochemically in the perikarya of numerous small-sized ganglion cells. The appearance of histochemically detectable ionic calcium in these cells in relation to the pharmacologically evoked degeneration of certain primary sensory neurons is discussed.

Physiology of the mammary glands.

ArticlesPhysiology of the Mammary GlandsJ. L. LinzellJ. L. LinzellPublished Online:01 Jul 1959https://doi.org/10.1152/physrev.1959.39.3.534MoreSectionsPDF (7 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByEstrogen increases calcitonin gene-related peptide-immunoreactive sensory innervation of rat mammary gland1 January 2004 | Journal of Neurobiology, Vol. 59, No. 2Differential Recruitment of T- and IgA B-lymphocytes in the Developing Mammary Gland in Relation to Homing Receptors and Vascular Addressins26 June 2016 | Journal of Histochemistry & Cytochemistry, Vol. 47, No. 12Udder characteristics in Toggenburg dairy goatsSmall Ruminant Research, Vol. 2, No. 2The effects of neonatal capsaicin treatment on the sensory innervation of the nipple and on the milk ejection reflex in the ratExperimental Brain Research, Vol. 73, No. 1Ultrasonic doppler study of the hormonal response of blood flow in the normal human breastUltrasound in Medicine & Biology, Vol. 13, No. 3Afferent projections from the mammary glands to the spinal cord in the lactating rat—II. Electrophysiological responses of spinal neurons during stimulation of the nipples, including sucklingNeuroscience, Vol. 19, No. 2Milk yield and composition in mice: Effects of litter size and lactation numberComparative Biochemistry and Physiology Part A: Physiology, Vol. 84, No. 1Drip breast milk: its composition, collection and pasteurizationEarly Human Development, Vol. 1, No. 3Some Neglected Aspects of the Anatomy of Human BreastsJournal of Investigative Dermatology, Vol. 63, No. 1The Mammary Glands of Rhesus MonkeysJournal of Investigative Dermatology, Vol. 63, No. 1Trifluperidol-Induged Lactation26 April 2017 | Canadian Psychiatric Association Journal, Vol. 19, No. 1A simple technique for measuring the rate of milk secretion in the ratComparative Biochemistry and Physiology Part A: Physiology, Vol. 43, No. 2Enzyme activities and electronmicroscopic structure of rat milk fractions obtained after centrifugationZeitschrift f�r Zellforschung und mikroskopische Anatomie, Vol. 131, No. 2Rate of growth and intake of milk in a suckling echidnaComparative Biochemistry and Physiology, Vol. 16, No. 4The effects of weaning and milk on mammary fatty acid synthesisBiochimica et Biophysica Acta (BBA) - Specialized Section on Lipids and Related Subjects, Vol. 84, No. 3INHIBITION OF LACTOGENESIS BY COMBINED ORAL PROGESTOGENS AND ŒSTROGENSThe Lancet, Vol. 282, No. 7303 More from this issue > Volume 39Issue 3July 1959Pages 534-576 https://doi.org/10.1152/physrev.1959.39.3.534PubMed13674904History Published online 1 July 1959 Published in print 1 July 1959 Metrics