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Cranial nerve 13. HANDBOOK OF CLINICAL NEUROLOGY 2019. [PMID: 31604543 DOI: 10.1016/b978-0-444-63855-7.00009-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Contrary to popular belief, there are 13 cranial nerves. The thirteenth cranial nerve, commonly referred to as the nervus terminalis or terminal nerve, is a highly conserved multifaceted nerve found just above the olfactory bulbs in humans and most vertebrate species. In most forms its fibers course from the rostral portion of the brain to the olfactory and nasal epithelia. Although there are differing perspectives as to what constitutes this nerve, in most species GnRH-immunoreactive neurons appear to be its defining feature. The involvement of this trophic peptide, as well as the nerve's association with the development of the hypothalamic-pituitary-gonadal axis, suggest a primary role in reproductive development and, in humans, disorders such as Kallmann syndrome. In some species, this enigmatic nerve appears to influence sensory processing, sexual behavior, autonomic and vasomotor control, and pathogenic defense (via secretion of nitric oxide). In this review, we provide a general overview of what is known about this neglected cranial nerve, with the goal of informing neurologists and neuroscientists of its presence and the need for its further study.
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Williams MB, Hernandez J, Thompson I. LUTEINIZING HORMONE-RELEASING HORMONE AGONIST EFFECTS ON SKELETAL MUSCLE: HOW HORMONAL THERAPY IN PROSTATE CANCER AFFECTS MUSCULAR STRENGTH. J Urol 2005; 173:1067-71. [PMID: 15758703 DOI: 10.1097/01.ju.0000143193.81585.5c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Since the discovery of Huggins in 1941 demonstrating the androgen dependence of prostate cancer cells, the use of pharmacological therapies to decrease systemic androgen concentrations has been one of the main treatment options for prostate cancer. Despite their efficacy luteinizing hormone releasing hormone agonists (LHRHas) have a number of side effects, of which many have not been fully investigated in humans. This review focuses on the effects of LHRHas on skeletal muscle in 3 main areas, namely effects at the androgen receptor, at the neuromuscular junction and on skeletal muscle myofibers. Since prostate cancer is predominantly a disease of elderly individuals, the aging effects of LHRHa therapy on skeletal muscle are magnified and of clinical importance. MATERIALS AND METHODS A comprehensive MEDLINE search was performed of pertinent studies in the literature relating to the use of LHRHa and skeletal muscle. RESULTS LHRHas affect 3 primary sites within the skeletal muscle system, namely androgen receptor, the neuromuscular junction and second messenger systems, including insulin-like growth factor-1. All sites have been demonstrated to lead to a decrease in isokinetic exercise strength in large muscle groups. CONCLUSIONS The musculoskeletal effects of LHRHas for the treatment of prostate cancer should be counteracted via a program of exercise strength training to decrease the morbidity associated with skeletal muscle weakness.
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Affiliation(s)
- Y Sakuma
- Department of Physiology, Nippon Medical School, Sendagi 1, Bunkyo, Tokyo 113, Japan.
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Secondary nicotinic synapses on sympathetic B neurons and their putative role in ganglionic amplification of activity. J Neurosci 2000. [PMID: 10648695 DOI: 10.1523/jneurosci.20-03-00908.2000] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The strength and number of nicotinic synapses that converge on secretomotor B neurons were assessed in the bullfrog by recording intracellularly from isolated preparations of paravertebral sympathetic ganglia 9 and 10. One input to every B neuron invariably produced a suprathreshold EPSP and was defined as the primary nicotinic synapse. In addition, 93% of the cells received one to four subthreshold inputs that were defined as secondary nicotinic synapses. This contradicts the prevailing view, which has long held that amphibian B neurons are singly innervated. More important, the results revealed that B cells provide the simplest possible experimental system for examining the role of secondary nicotinic synapses on sympathetic neurons. Combining the convergence data with previous estimates of divergence indicates that the average preganglionic B neuron forms connections with 50 ganglionic B neurons and that the majority of these nicotinic synapses are secondary in strength. Secondary EPSPs evoked by low-frequency stimulation ranged from 0.5 to 10 mV in amplitude and had an average quantal content of 1. Nonetheless, secondary synapses could trigger action potentials via four mechanisms: spontaneous fluctuations of EPSP amplitude, two-pulse facilitation, coactivation with other secondary synapses, and coactivation with a slow peptidergic EPSP. The data were used to formulate a stochastic theory of integration, which predicts that ganglia function as amplifiers of the sympathetic outflow. In this two-component scheme, primary nicotinic synapses mediate invariant synaptic gain, and secondary nicotinic synapses mediate activity-dependent synaptic gain. The model also provides a common framework for considering how facilitation, metabotropic mechanisms, and preganglionic oscillators regulate synaptic amplification in sympathetic ganglia.
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Affiliation(s)
- P A Smith
- Department of Pharmacology, University of Alberta, Edmonton, Canada
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Pant KK, Smith PA. Atrial natriuretic factor suppresses M-current in frog but not in rat sympathetic neurones. Neurosci Lett 1989; 100:243-8. [PMID: 2527344 DOI: 10.1016/0304-3940(89)90692-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of atrial natriuretic factor (ANF) were investigated on rat and bullfrog sympathetic ganglia. Although there was little effect on neurones from rat superior cervical ganglion (SCG), B-cells in bullfrog paravertebral ganglia (BFSG) were depolarized. This depolarization was often associated with an increase in excitability and suppression of a voltage-dependent K+ current, the M-current (IM). ANF did not affect the amplitude of the nicotinic EPSP in either ganglion.
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Affiliation(s)
- K K Pant
- Department of Pharmacology, University of Alberta, Edmonton, Alta., Canada
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Akasu T, Tokimasa T. Modulation of the sensitivity of nicotinic receptors in autonomic ganglia. EXS 1989; 57:190-6. [PMID: 2533092 DOI: 10.1007/978-3-0348-9138-7_19] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This article reviews some of the evidence suggesting that a variety of endogenous substances either facilitates or inhibits the sensitivity of nicotinic acetylcholine (ACh) receptors at the subsynaptic membrane of cholinergic synapses. It is noteworthy that 5-hydroxytryptamine and histamine act as competitive antagonists, like curare, presumably changing the affinity of ACh for the specific binding site on the nicotinic receptor. Catecholamine, neuropeptides, prostaglandin and glucocorticoids act as non-competitive antagonists on an allosteric site on the receptor-ionic channel complex. ATP and LH-RH (in a subpopulation of sympathetic neurons) caused a facilitation of the sensitivity of nicotinic receptors. The mode of actions of endogenous substances which modulate the nicotinic receptor-sensitivity is similar to those of pharmacological agents. Therefore, these neurotransmitters and neurohormones have been termed endogenous 'antagonists' or 'sensitizers'.
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Affiliation(s)
- T Akasu
- Department of Physiology, Kurume University School of Medicine, Japan
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Pan JT, Kow LM, Pfaff DW. Modulatory actions of luteinizing hormone-releasing hormone on electrical activity of preoptic neurons in brain slices. Neuroscience 1988; 27:623-8. [PMID: 3146034 DOI: 10.1016/0306-4522(88)90293-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Single unit activity was recorded from 378 neurons, in two preoptic nuclei rich in luteinizing hormone-releasing hormone neurons, using in vitro brain tissue slices which were prepared form either ovariectomized or ovariectomized plus estradiol-treated rats. To test possible transmitter-like actions, agents were injected into the perfusion medium. Luteinizing hormone-releasing hormone excited 46%, inhibited 7%, and evoked biphasic responses in 2% of the 250 units tested. By comparison, two other peptides, thyrotropin-releasing hormone and cholecystokinin-octapeptide sulfated were exclusively excitatory, acting on 55 and 67% of the neurons, respectively. The response to thyrotropin-releasing hormone, cholecystokinin-octapeptide sulfated, and neurotransmitters were prompt, large, and consistent from trial to trial. In contrast, responses to luteinizing hormone-releasing hormone were usually delayed, small, and variable. Responses to the agents tested were not affected by in vivo estradiol treatment. Possible modulatory actions of luteinizing hormone-releasing hormone were tested by comparing the responses of single neurons to norepinephrine and serotonin before and after an application of luteinizing hormone-releasing hormone. In 39 and 20% of the 119 neurons tested, the norepinephrine responses were potentiated and attenuated, respectively, by luteinizing hormone-releasing hormone. In 46 serotonin-responsive neurons, 28% were potentiated and 22% attenuated. These neuromodulatory actions of luteinizing hormone-releasing hormone were specific in affecting only certain responses of certain neurons, and they were not duplicated on the same neurons by thyrotropin-releasing hormone. It appears that luteinizing hormone-releasing hormone may be a neuromodulator in the preoptic area.
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Affiliation(s)
- J T Pan
- Rockefeller University, New York, NY 10021
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Pfaff DW, Jorgenson K, Kow LM. Luteinizing hormone-releasing hormone in rat brain: gene expression, role as neuromodulator, and functional effects. Ann N Y Acad Sci 1987; 519:323-33. [PMID: 2896483 DOI: 10.1111/j.1749-6632.1987.tb36307.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- D W Pfaff
- Laboratory of Neurobiology and Behavior, Rockefeller University, New York, New York 10221
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Hasuo H, Akasu T. Luteinizing hormone-releasing hormone inhibits nicotinic transmission in bullfrog sympathetic ganglia. Neurosci Res 1986; 3:444-50. [PMID: 3528941 DOI: 10.1016/0168-0102(86)90036-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Intracellular and voltage-clamp recordings were made from neurons in bullfrog sympathetic ganglia to investigate the effects of luteinizing hormone-releasing hormone (LH-RH) on nicotinic transmission. LH-RH (50 nM-4 microM) decreased the amplitude of the fast excitatory postsynaptic potential (fast EPSP) in a dose-dependent manner. LH-RH (1-4 microM) reduced the quantal content of the fast EPSP by 60-85%. LH-RH did not change the frequency of the miniature (m) EPSP, but it slightly depressed the mEPSP amplitude. LH-RH (1-4 microM) caused a 22-32% decrease in the amplitude of the acetylcholine-induced synaptic responses due to the iontophoretic application of acetylcholine (ACh) to neurons in the presence of atropine (1 microM). These results suggested that LH-RH decreased nicotinic transmission in the bullfrog sympathetic ganglion, primarily by reducing the release of ACh from the preganglionic nerve terminals.
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Ariyoshi M, Akasu T. Glucocorticoid modulates the sensitivity of the GABAA receptor on primary afferent neurons of bullfrogs. Brain Res 1986; 367:332-6. [PMID: 3008924 DOI: 10.1016/0006-8993(86)91613-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
With intracellular and voltage-clamp recording techniques, we have demonstrated that the glucocorticoids, prednisolone and hydrocortisone at a concentration of 5 microM to 1 mM, reversibly depressed gamma-aminobutyric acid (GABA)-induced responses on primary afferent neurons of bullfrogs. An analysis with dose-response curves revealed that the glucocorticoids decreased the sensitivity of the GABAA receptor in a non-competitive manner. We suggest that glucocorticoids act as an antagonist of the GABAA receptor on primary afferent neurons, probably by reducing the number of functional GABAA receptor ionic channel complexes.
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Abstract
The large B cells of bull-frog sympathetic ganglia are well known to be depolarized by slow synaptic transmission, muscarinic agonists, analogues of luteinizing hormone-releasing hormone (LHRH), and substance P. Voltage-clamp analysis shows that these actions result from two underlying mechanisms: inhibition of the M-current, a voltage-dependent potassium current; and in some cells, an inward current associated with an increase in conductance. The additional inward current appears as a voltage-insensitive change in the instantaneous conductance (i.e. apparent leak conductance). The additional inward current is typically slower in onset and offset than is M-current inhibition. It is typically seen for higher concentrations and longer durations of agonist application. In many cells, only a decrease in M-current can be demonstrated. Muscarine inhibits the M-current with 50% inhibition (I50) at 0.7 microM. At least 86% of the M-current is muscarine sensitive. At comparable concentrations, oxotremorine produces less M-current inhibition than does muscarine. Some analogues of teleost LHRH (T-LHRH) are more potent as M-current inhibitors than T-LHRH itself. Those peptides tend to act more slowly than T-LHRH. Substance P shows variable potency for M-current inhibition, with I50 s ranging from 2 nM to greater than 2 microM on different cells. The response to long applications of substance P desensitizes in some cells, which has not been observed for comparable applications of muscarinic or LHRH agonists. Other tachykinins (including substance K) inhibit the M-current. C-terminal fragments of substance P are ineffective, and M-current inhibition by substance P is not blocked by [D-Pro2,D-Trp7,9]- or [D-Arg1,D-Pro2, D-Trp7,9,Leu11] substance P. The slow muscarinic excitatory post-synaptic potential (e.p.s.p.) produces a graded inhibition of up to 90% of the M-current. Occasional cells show an additional inward current with an associated increase in conductance during the slow e.p.s.p. This effect is less marked than with exogenous muscarinic agonists. The late, slow e.p.s.p., which is produced by stimulation of high threshold C-fibre inputs and is resistant to cholinergic antagonists, also involves M-current inhibition. An additional inward current can be observed in some cells. M-current inhibition (by agonists or slow synaptic potentials) increases the number of spikes produced by a given depolarizing current, often allowing maintained firing. This action is not mimicked by equivalent depolarization, and is still seen when the cell is manually clamped to the original resting potential.(ABSTRACT TRUNCATED AT 400 WORDS)
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Barker JL, Dufy B. Peptide and amino acid electropharmacology of cultured mammalian central neurons and clonal pituitary cells. REGULATORY PEPTIDES. SUPPLEMENT 1985; 4:14-22. [PMID: 2414811 DOI: 10.1016/0167-0115(85)90211-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Akasu T, Ohta Y, Koketsu K. Neuropeptides facilitate the desensitization of nicotinic acetylcholine-receptor in frog skeletal muscle endplate. Brain Res 1984; 290:342-7. [PMID: 6198044 DOI: 10.1016/0006-8993(84)90953-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Substance P and luteinizing hormone-releasing hormone (LHRH), neurotransmitter candidates for peptidergic neurotransmission in peripheral autonomic ganglia, facilitated the desensitization of nicotinic acetylcholine (ACh)-receptor at the skeletal muscle endplate. In the presence of these peptides, the desensitization proceeded with a biphasic time course, i.e. fast and then slow components of desensitization. We suggest that neuropeptides such as substance P and LHRH may regulate the sensitivity of nicotinic ACh-receptors by modulating the process of desensitization.
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Barker JL, Dufy B, Owen DG, Rogawski MA. Electrophysiological studies of peptide actions on the excitability of cultured nerve and pituitary cells. CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1984; 6:1701-16. [PMID: 6152408 DOI: 10.3109/10641968409046064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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