Varicose axons bearing ?synaptic? vesicles on the basal lamina of the human seminiferous tubules

Nistal, Manuel; Paniagua, Ricardo; Abaurrea, María Asunción

doi:10.1007/bf00217083

Cited by 25 publications

(15 citation statements)

References 13 publications

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“…Documented close anatomical proximity between neuronal elements and testicular cells (Leydig cells, cells of the tubular wall and vascular cells [cf. 25, 26, 27]) in vivo, make testicular cells direct targets of catecholamines and neuropeptides and provide further evidence for a functional link. It is possible that while all Leydig cells in the adult may be subjected to regulation by LH, some, the ones contacted by neuronal element in particular, may be subjected to dual regulation, one by pituitary LH and one by catecholamines and/or neurotransmitters.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, both the number of mast cells and the number of nerve fibers in monkey testes increased after puberty and are thus inversely related to the number of neuron-like cells. Previous reports described age-dependent increases in the number of testicular mast cells occurring around puberty in hamster, rat and human testes [20, 25, 67], and mast cells and Leydig cells, which developed simultaneously after chemical destruction of Leydig cells in the rat [67]. Mast cells produce biologically highly active substances, including proteases, cytokines, histamine and serotonin, which can be released in response to different stimuli [19, 67].…”

Section: Discussionmentioning

confidence: 99%

“…Compared to the bloodstream, the innervation may allow a more precise way of delivery neurotransmitters to target cell in the testis. Indeed testicular nerve fibers form ‘synapses en passant’ with Leydig cells and peritubular cells in the human testis [25, 26, 27], implicating release of neurotransmitters into the interstitial space in the close neighborhood of the targets. Moreover, testicular innervation, appears also to be important for a functional direct link between testes and brain [cf.…”

Section: Introductionmentioning

confidence: 99%

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Neuronal Elements in the Testis of the Rhesus Monkey: Ontogeny, Characterization and Relationship to Testicular Cells

et al. 2000

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Intrinsic neuron-like cells expressing the catecholamine-biosynthetic enzyme tyrosine hydroxylase (TH) were recently identified in the testis of the prepubertal rhesus monkey. In this study, we characterized the neuron-like nature of these cells and examined distribution and frequency of neuronal elements in the testes of monkeys during postnatal development, puberty and adulthood. Using immunohistochemical methods, we detected both nerve fibers and cell bodies, immunoreactive for the neuronal markers neurofilament 200 (NF-200) and synaptosomal associated protein of 25 kDa (SNAP-25), TH and neuropeptide Y (NPY) in perivascular locations, intermingled with interstitial cells and close to the wall of seminiferous tubules. Marked age-related differences in the numbers of these neuronal elements became apparent, when we quantified NF-200-immunoreactive neuronal elements. Thus, intrinsic neuron-like cell bodies were found only in the testes from immature animals (i.e., until about 3 years of age). Conversely, nerve fibers, presumably representing mainly the extrinsic innervation, were observed at all ages although they became more prominent after the pubertal increase in LH and testosterone levels. Interestingly, another testicular cell type known to contain potent regulatory substances, mast cells, was found to be in close anatomical proximity to nerve fibers. The number of these cells, positively identified with an antibody to tryptase, increased significantly after puberty following the same pattern as nerve fibers. These results confirm that the testicular nervous system of the monkey is composed of two components, intrinsic nerve cells and extrinsic fibers, both of which are catecholaminergic and peptidergic in nature. Furthermore, both components show a marked degree of plasticity during development, especially around the time of puberty. The intratesticular locations of neuron-like cells and fibers suggest that catecholamines and neuropeptides are likely to have multiple sites of actions, and may affect Leydig cells, cells of the tubular wall and vascular cells directly and/or indirectly via intermediation of mast cells.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neuronal Elements in the Testis of the Rhesus Monkey: Ontogeny, Characterization and Relationship to Testicular Cells

et al. 2000

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“…These results suggest that SCI is associated with altered FSH/FSH-R and/or testosterone/androgen receptor signal events in Sertoli cells. Although evidence for a direct innervation of Sertoli cells is still lacking [33, 34], neural regulation of Sertoli cell functions has been implicated by findings demonstrating modulation of Sertoli cell functions by neurotransmitters and related molecules. The effects of FSH on Sertoli cell proliferation [35]and secretion of inhibin [36]and androgen-binding protein [37]have been shown to be modulated by β-endorphin, attributable to the presence of opiate receptors in Sertoli cells [38].…”

Section: Discussionmentioning

confidence: 99%

The Effects of Testicular Denervation on Spermatogenesis in the Sprague- Dawley Rat

Chow¹,

Giglio

Anesetti

et al. 2000

Neuroendocrinology

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In the rat, regression of spermatogenesis during the chronic stages of spinal cord injury (SCI) occurs in the presence of normal function of the pituitary-testis hormone axis, thus suggesting that nonendocrine mechanisms might be involved. The current study examined whether disruption of neural input to the testis contributes to the cascade that leads to the regression of spermatogenesis. Four weeks after denervation of the superior spermatic nerve (SSN), testis weight was 25% lower (p < 0.01) than that of the contralateral sham-operated testis. Defects in spermatogenesis including phagocytosis of mature spermatids, vacuolization of spermatid nuclei, delayed spermiation and incomplete cellular associations were observed in >60% of the tubules. In the remaining 30–40% of tubules, the seminiferous epithelium was severely regressed. While cutting the inferior spermatic nerve (ISN) alone did not affect spermatogenesis significantly, it enhanced the effect of SSN denervation on both spermatogenesis and testis weight (p < 0.01). Spermatogenesis was totally regressed in the SSN/ISN-denervated testes. At this time, quantitatively normal spermatogonial proliferation was maintained in SSN- or ISN-denervated testes. Twelve weeks after surgery, regression of the seminiferous epithelium characterized by absence of proliferating spermatogonia, while undifferentiating spermatogonia were present, was observed in all SSN-denervated testes. At this time, regression of the seminiferous epithelia also occurred in >30% of the tubules in ISN-denervated testes. At both times, serum follicle-stimulating hormone, luteinizing hormone and testosterone levels were normal and >60% of normal testicular testosterone concentrations were maintained in the denervated testes. These results indicate that disruption of neural input to the testis is not a cause for the decrease in spermatogonial proliferation during the acute phase of SCI, but may contribute to the chronic effects of SCI on spermatogenesis.

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“…Nerves are numerous in the testis of human, rhesus monkey, and cat (Nistal et al 1982, Prince, 1992Setchell et al, 1994;Mayerhofer, 1996), whereas they are restricted to the testicular capsule and larger portions of the testicular artery in the rat (Zhu et al, 1995), guinea pig (Carvalho et al, 1986), bull (Wrobel and Abu-Ghalil, 1997), pig (Wrobel and Brandl, 1998), and donkey (Wrobel and Mustafa, 2000). Thus, the cat is the only known species whose innervation resembles that of primates.…”

mentioning

confidence: 99%

Peptidergic Innervation of Blood Vessels and Interstitial Cells in the Testis of the Cat

Suburo

Chiocchio

Soler

et al. 2002

Journal of Andrology

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ABSTRACT:We studied the innervation of the cat testis using a panel of antisera against the following neuronal markers: protein gene product 9.5 (PGP), neuropeptide Y, C-terminal peptide of neuropeptide Y, galanin, vasoactive intestinal peptide (VIP), calcitonin gene-related peptide, and substance P. Immunoreactivity against PGP, a general neuronal label, demonstrated the arrangement of fibers from the superior spermatic nerve (SSN) in the testicular pedicle and the cephalic testicular pole, and those of the inferior spermatic nerve (ISN) along the vas deferens and the inferior testicular ligament. The testicular parenchyma exhibited a very rich innervation, mainly distributed to blood vessels and Leydig cell nests, but also in close association with seminiferous tubules. Numerous peptidergic fibers were present in the SSN and ISN, albeit in different proportions. Thus, VIP-immunoreactive fibers were almost absent in the SSN, but were the most abundant subpopulation of the ISN. The testicular interstitium contained numerous peptidergic fibers, associated with blood vessels, interstitial Leydig cells, and seminiferous tubules. Similar fibers were related to the rete testis. Parenchymatous VIP-immunoreactive nerves disappeared after bilateral vasectomy. Stimulation of the ISN under experimental conditions was associated with an increase of blood flow, and induced a large release of VIP into the spermatic vein. The extensive and selective distribution of nerve fibers within the cat testicular parenchyma supports the importance of spermatic nerves for testicular function. Furthermore, the differences in the fiber composition of the SSN and ISN can be correlated with their opposing effects on testosterone secretion and testicular blood flow.

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Varicose axons bearing ?synaptic? vesicles on the basal lamina of the human seminiferous tubules

Cited by 25 publications

References 13 publications

Neuronal Elements in the Testis of the Rhesus Monkey: Ontogeny, Characterization and Relationship to Testicular Cells

Neuronal Elements in the Testis of the Rhesus Monkey: Ontogeny, Characterization and Relationship to Testicular Cells

The Effects of Testicular Denervation on Spermatogenesis in the Sprague- Dawley Rat

Peptidergic Innervation of Blood Vessels and Interstitial Cells in the Testis of the Cat

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