1
|
Gundacker A, Cuenca Rico L, Stoehrmann P, Tillmann KE, Weber-Stadlbauer U, Pollak DD. Interaction of the pre- and postnatal environment in the maternal immune activation model. DISCOVER MENTAL HEALTH 2023; 3:15. [PMID: 37622027 PMCID: PMC10444676 DOI: 10.1007/s44192-023-00042-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023]
Abstract
Adverse influences during pregnancy are associated with a range of unfavorable outcomes for the developing offspring. Maternal psychosocial stress, exposure to infections and nutritional imbalances are known risk factors for neurodevelopmental derangements and according psychiatric and neurological manifestations later in offspring life. In this context, the maternal immune activation (MIA) model has been extensively used in preclinical research to study how stimulation of the maternal immune system during gestation derails the tightly coordinated sequence of fetal neurodevelopment. The ensuing consequence of MIA for offspring brain structure and function are majorly manifested in behavioral and cognitive abnormalities, phenotypically presenting during the periods of adolescence and adulthood. These observations have been interpreted within the framework of the "double-hit-hypothesis" suggesting that an elevated risk for neurodevelopmental disorders results from an individual being subjected to two adverse environmental influences at distinct periods of life, jointly leading to the emergence of pathology. The early postnatal period, during which the caregiving parent is the major determinant of the newborn´s environment, constitutes a window of vulnerability to external stimuli. Considering that MIA not only affects the developing fetus, but also impinges on the mother´s brain, which is in a state of heightened malleability during pregnancy, the impact of MIA on maternal brain function and behavior postpartum may importantly contribute to the detrimental consequences for her progeny. Here we review current information on the interaction between the prenatal and postnatal maternal environments in the modulation of offspring development and their relevance for the pathophysiology of the MIA model.
Collapse
Affiliation(s)
- Anna Gundacker
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse, 17, 1090 Vienna, Austria
| | - Laura Cuenca Rico
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse, 17, 1090 Vienna, Austria
| | - Peter Stoehrmann
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse, 17, 1090 Vienna, Austria
| | - Katharina E. Tillmann
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse, 17, 1090 Vienna, Austria
| | - Ulrike Weber-Stadlbauer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Daniela D. Pollak
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse, 17, 1090 Vienna, Austria
| |
Collapse
|
2
|
Rajkumar R, Dawe GS. OBscure but not OBsolete: Perturbations of the frontal cortex in common between rodent olfactory bulbectomy model and major depression. J Chem Neuroanat 2018; 91:63-100. [DOI: 10.1016/j.jchemneu.2018.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 03/02/2018] [Accepted: 04/04/2018] [Indexed: 02/08/2023]
|
3
|
Chen JR, Lim SH, Chung SC, Lee YF, Wang YJ, Tseng GF, Wang TJ. Reproductive experience modified dendritic spines on cortical pyramidal neurons to enhance sensory perception and spatial learning in rats. Exp Anim 2016; 66:61-74. [PMID: 27784858 PMCID: PMC5301002 DOI: 10.1538/expanim.16-0061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Behavioral adaptations during motherhood are aimed at increasing reproductive success.
Alterations of hormones during motherhood could trigger brain morphological changes to
underlie behavioral alterations. Here we investigated whether motherhood changes a rat’s
sensory perception and spatial memory in conjunction with cortical neuronal structural
changes. Female rats of different statuses, including virgin, pregnant, lactating, and
primiparous rats were studied. Behavioral test showed that the lactating rats were most
sensitive to heat, while rats with motherhood and reproduction experience outperformed
virgin rats in a water maze task. By intracellular dye injection and computer-assisted
3-dimensional reconstruction, the dendritic arbors and spines of the layer III and V
pyramidal neurons of the somatosensory cortex and CA1 hippocampal pyramidal neurons were
revealed for closer analysis. The results showed that motherhood and reproductive
experience increased dendritic spines but not arbors or the lengths of the layer III and V
pyramidal neurons of the somatosensory cortex and CA1 hippocampal pyramidal neurons. In
addition, lactating rats had a higher incidence of spines than pregnant or primiparous
rats. The increase of dendritic spines was coupled with increased expression of the
glutamatergic postsynaptic marker protein (PSD-95), especially in lactating rats. On the
basis of the present results, it is concluded that motherhood enhanced rat sensory
perception and spatial memory and was accompanied by increases in dendritic spines on
output neurons of the somatosensory cortex and CA1 hippocampus. The effect was sustained
for at least 6 weeks after the weaning of the pups.
Collapse
Affiliation(s)
- Jeng-Rung Chen
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan
| | | | | | | | | | | | | |
Collapse
|
4
|
Morin LP, Studholme KM. Retinofugal projections in the mouse. J Comp Neurol 2014; 522:3733-53. [PMID: 24889098 PMCID: PMC4142087 DOI: 10.1002/cne.23635] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/28/2014] [Accepted: 05/28/2014] [Indexed: 12/24/2022]
Abstract
The laboratory mouse is increasingly a subject for visual system investigation, but there has been no comprehensive evaluation of this species' visual projections. Here, projections were visualized and mapped following intraocular injection of cholera toxin B subunit. Tissue was processed using standard procedures applied to 30 μm free-floating sections with diaminobenzidine as the chromogen. The mouse retina projects to ~46 brain regions, including 14 not previously described in this species. These include two amygdaloid nuclei, the horizontal limb of the diagonal band, the paraventricular hypothalamic nucleus, several visual thalamic nuclei, the paranigral nucleus, several pretectal nuclei, and the dorsal cortex of the inferior colliculus. Dense retinal patches were also observed in a narrow portion of the ipsilateral intermediate layer of the superior colliculus. The superior fasciculus of the accessory optic tract, which innervates the medial terminal nucleus, was also determined to be a terminal zone throughout its length. The results are compared with previous descriptions of projections from mouse intrinsically photoreceptive retinal ganglion cells, and with data from the hamster, Nile grass rat, and laboratory rat. The retinal projection patterns are similar in all four species, although there are many differences with respect to the details. The specific visual functions of most retinorecipient areas are unknown, but there is substantial convergence of retinal projections onto regions concerned with olfaction and audition.
Collapse
Affiliation(s)
- Lawrence P Morin
- Department of Psychiatry, Stony Brook University Medical Center, Stony Brook, NY, 11794-8101; Graduate Program in Neuroscience, Stony Brook University Medical Center, Stony Brook, NY, 11794-8101
| | | |
Collapse
|
5
|
Walton JC, Pyter LM, Weil ZM, Nelson RJ. Photoperiod mediated changes in olfactory bulb neurogenesis and olfactory behavior in male white-footed mice (Peromyscus leucopus). PLoS One 2012; 7:e42743. [PMID: 22912730 PMCID: PMC3415390 DOI: 10.1371/journal.pone.0042743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 07/12/2012] [Indexed: 12/24/2022] Open
Abstract
Brain plasticity, in relation to new adult mammalian neurons generated in the subgranular zone of the hippocampus, has been well described. However, the functional outcome of new adult olfactory neurons born in the subventricular zone of the lateral ventricles is not clearly defined, as manipulating neurogenesis through various methods has given inconsistent and conflicting results in lab mice. Several small rodent species, including Peromyscus leucopus, display seasonal (photoperiodic) brain plasticity in brain volume, hippocampal function, and hippocampus-dependent behaviors; plasticity in the olfactory system of photoperiodic rodents remains largely uninvestigated. We exposed adult male P. leucopus to long day lengths (LD) and short day lengths (SD) for 10 to 15 weeks and then examined olfactory bulb cell proliferation and survival using the thymidine analog BrdU, olfactory bulb granule cell morphology using Golgi-Cox staining, and behavioral investigation of same-sex conspecific urine. SD mice did not differ from LD counterparts in granular cell morphology of the dendrites or in dendritic spine density. Although there were no differences due to photoperiod in habituation to water odor, SD mice rapidly habituated to male urine, whereas LD mice did not. In addition, short day induced changes in olfactory behavior were associated with increased neurogenesis in the caudal plexiform and granule cell layers of the olfactory bulb, an area known to preferentially respond to water-soluble odorants. Taken together, these data demonstrate that photoperiod, without altering olfactory bulb neuronal morphology, alters olfactory bulb neurogenesis and olfactory behavior in Peromyscus leucopus.
Collapse
Affiliation(s)
- James C Walton
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America.
| | | | | | | |
Collapse
|
6
|
Reproductive responses to photoperiod persist in olfactory bulbectomized Siberian hamsters (Phodopus sungorus). Behav Brain Res 2008; 198:159-64. [PMID: 19027041 DOI: 10.1016/j.bbr.2008.10.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 09/22/2008] [Accepted: 10/26/2008] [Indexed: 11/23/2022]
Abstract
In reproductively photoperiodic Syrian hamsters, removal of the olfactory bulbs (OBx) leads to a marked and sustained increase in gonadotrophin secretion which prevents normal testicular regression in short photoperiods. In contrast, among reproductively nonphotoperiodic laboratory strains of rats and mice, bulbectomy unmasks reproductive responses to photoperiod. The role of the olfactory bulbs has been proposed to have opposite effects on responsiveness to photoperiod, depending on the photoperiodicity of the reproductive system; however, Syrian hamsters are the only reproductively photoperiodic rodent species for which the role of the olfactory bulb in reproductive endocrinology has been assessed. This experiment evaluated the role of the olfactory bulbs in the photoperiodic control of reproduction in Siberian hamsters (Phodopus sungorus), an established model species for the study of neural substrates mediating seasonality. Relative to control hamsters housed in long days (15 h light/day), exposure of adult male hamsters to short days (9h light/day) for 8 weeks led to a temporal expansion of the pattern of nocturnal locomotor activity, testicular regression, decreases in testosterone (T) production, and undetectable levels of plasma follicle-stimulating hormone (FSH). Bilateral olfactory bulbectomy failed to affect any of these responses to short days. The patterns of entrainment to long and short days suggests that pre-pineal mechanisms involved in photoperiodic timekeeping are functioning normally in OBx hamsters. The absence of increases in FSH following bulbectomy in long days is incompatible with the hypothesis that the olfactory bulbs provide tonic inhibition of the HPG axis in this species. In marked contrast to Syrian hamsters, the olfactory bulbs of Siberian hamsters play essentially no role in the modulation of tonic gonadotrophin production or gonadotrophin responses to photoperiod.
Collapse
|
7
|
Bae HH, Mangels RA, Cho BS, Dark J, Yellon SM, Zucker I. Ventromedial hypothalamic mediation of photoperiodic gonadal responses in male Syrian hamsters. J Biol Rhythms 1999; 14:391-401. [PMID: 10511006 DOI: 10.1177/074873099129000795] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Short day lengths induce testicular regression in seasonally breeding Syrian hamsters. To test whether the ventromedial hypothalamus is necessary to maintain reproductive quiescence once testicular regression has been achieved, photoregressed male hamsters were subjected to lesions of the ventromedial hypothalamus (VMHx), pinealectomy (Pinx), or sham operation (Sham). VMHx hamsters underwent accelerated gonadal recrudescence compared to Pinx and Sham hamsters. Recovery of prolactin concentrations (PRL) to values characteristic of long-day hamsters was hastened in the VMHx animals compared to Sham hamsters. Concentrations of follicle stimulating hormone (FSH) increased prematurely in both the VMHx and Pinx animals, beginning a few weeks after surgery. By the time the gonads had undergone recrudescence and the hamsters were refractory to melatonin, PRL and FSH concentrations had returned to baseline long-day values in all groups; there was no evidence of hypersecretion of either hormone in any of the animals with lesions. Melatonin concentrations of VMHx hamsters did not differ from those of sham-operated animals, but because only a single determination was made, it remains possible that VMH damage altered the duration of nightly melatonin secretion. An intact VMH appears to be essential for the continued maintenance of reproductive suppression induced by exposure to short day lengths; these and earlier findings suggest that the VMH-dorsomedial hypothalamic complex mediates regression of the reproductive apparatus during decreasing day lengths of late summer and early autumn and also is necessary to sustain regression during the winter months.
Collapse
Affiliation(s)
- H H Bae
- Group in Endocrinology in the Department of Integrative Biology, University of California at Berkeley 94720, USA
| | | | | | | | | | | |
Collapse
|
8
|
Pieper DR, Newman SW. Neural pathway from the olfactory bulbs regulating tonic gonadotropin secretion. Neurosci Biobehav Rev 1999; 23:555-62. [PMID: 10073893 DOI: 10.1016/s0149-7634(98)00049-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Removal of the olfactory bulbs of male golden hamsters results in a marked increase in tonic gonadotropin, prolactin and testosterone secretion which counteracts inhibitory effects of manipulations such as maintenance on short photoperiod, food restriction or treatment with gonadal steroids. The bulbectomy-induced increase in hormone secretion is interpreted to reflect a tonic inhibitory influence of the olfactory bulbs. This inhibition is not dependent upon chemosensory stimulation and may be mediated by olfactory bulb fibers projecting through the lateral olfactory tract to or through the olfactory tubercle. This review will relate these studies conducted on hamsters to results in other species, such as the rat, where the olfactory bulbs enhance serum gonadotropin levels.
Collapse
Affiliation(s)
- D R Pieper
- Providence Hospital, Department of Physiology, Southfield, MI 48037, USA.
| | | |
Collapse
|
9
|
Hegstrom CD, Breedlove SM. Social cues attenuate photoresponsiveness of the male reproductive system in Siberian hamsters (Phodopus sungorus). J Biol Rhythms 1999; 14:54-61. [PMID: 10036993 DOI: 10.1177/074873099129000443] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Transfer of adult Siberian hamsters (Phodopus sungorus) from long (16 h light and 8 h dark, 16L:8D) to short (8L:16D) daily photoperiods induces an involution of the gonads and a cessation of reproductive behavior 8 to 10 weeks later. However, when male and female long-day hamsters were paired on transfer to short photoperiods, the males' gonads did not undergo the typical short-day response. Similarly, when male long-day hamsters were paired with refractory females (i.e., females housed in short photoperiods for at least 28 weeks so that they became unresponsive to short photoperiods), the response of the males' reproductive system to short photoperiods also was attenuated. Thus, social cues can override or delay the effects of photoperiod on the testes of this species. These results suggest that the inhibitory effects of long durations of melatonin secretion (in response to short photoperiods) on the male hypothalamic-pituitary-gonadal axis may be attenuated by social cues such as contact with the opposite sex.
Collapse
Affiliation(s)
- C D Hegstrom
- Department of Psychology, University of California, Berkeley 94720-1650, USA
| | | |
Collapse
|
10
|
Goel N, Lee TM, Pieper DR. Removal of the olfactory bulbs delays photic reentrainment of circadian activity rhythms and modifies the reproductive axis in male Octodon degus. Brain Res 1998; 792:229-36. [PMID: 9593909 DOI: 10.1016/s0006-8993(98)00134-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The diurnal rodent, Octodon degus, exhibits robust sex differences in several circadian measures, including circadian period (tau) and reentrainment rates to photic and nonphotic (social) zeitgebers. The neural substrates underlying such physiological differences remain unknown. In female degus, olfactory bulbectomies (BX) inhibit socially-facilitated reentrainment, but do not alter photic reentrainment, entrained measures, or tau in constant darkness (DD). This experiment investigated the effects of BX in male degus on (i) photic reentrainment rates of circadian rhythms following a 6-h phase advance of the light-dark (LD) cycle; (ii) photic entrainment; (iii) tau of free-running activity rhythms in DD; and (iv) body weight, paired testis weight, and the reproductive hormones, testosterone, androstenedione and follicle stimulating hormone (FSH). BX significantly delayed photic reentrainment rates. They did not, however, modify tau, the phase of activity onset or offset, amplitude or duration (alpha) of the activity rhythm, mean daily locomotor activity levels, or body weight. FSH, testosterone and androstenedione were unaffected by BX, whereas paired testis weights were significantly greater in BX degus compared with shams. Thus, the olfactory bulbs influence photic reentrainment of circadian rhythms and modestly affect the reproductive axis in male degus. Our results suggest that the olfactory bulbs may be a neural source of observed sex differences in photic reentrainment in degus, and highlight interspecies variation in the olfactory bulbs' effects on entrained and free-running circadian rhythms and on reproduction.
Collapse
Affiliation(s)
- N Goel
- Department of Psychology, 525 East University, University of Michigan, Ann Arbor, MI 48109, USA.
| | | | | |
Collapse
|
11
|
Gomez DM, Newman SW, Pieper DR. Lesions of the ventral striatum mimic the effect of olfactory bulbectomy to prevent short photoperiod-induced testicular regression in golden hamsters. Brain Res 1996; 723:148-53. [PMID: 8813392 DOI: 10.1016/0006-8993(96)00234-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Bilateral olfactory bulbectomy (BX) or bilateral transection of the rostral lateral olfactory tract (LOT) at the level of the anterior olfactory nucleus markedly increases gonadotropin secretion and prevents the testicular regression associated with maintenance on short photoperiod in golden hamsters. In an effort to further elucidate the neural tracts involved in this influence on gonadotropin secretion, lesions were placed in several potential pathways. Hamsters underwent sham surgery (SH), bilateral BX, or electrolytic or radiofrequency lesions of the: medial nucleus of the amygdala (MeX) caudal LOT just rostral to the medial nucleus of the amygdala (LOTX); or ventral striatum (VSX). Lesions were either bilateral or unilateral with contralateral olfactory bulbectomy. All animals were then placed on short photoperiod (LD 10:14) for 10 weeks and testicular size and body weight were assessed at weekly intervals. Lesion placement was assessed in brain sections stained with cresyl violet and animals with misplaced lesions were excluded. The following represent the number of animals in each group undergoing testicular regression in response to short photoperiod: SH: 32/35; BX: 8/31 (P < 0.01 vs. SH); MeX: 5/5; caudal LOTX: 8/9 and VSX: 3/8 (P < 0.05 vs. SH). Serum LH, FSH and testosterone at the end of the study correlated with the testicular regression data. These results suggest that the tonic inhibitory effect of the olfactory bulbs on gonadotropin secretion is mediated by fibers that exit the LOT rostral to the amygdala and project medially, either passing through or synapsing in the ventral striatum.
Collapse
Affiliation(s)
- D M Gomez
- University of Michigan, Department of Anatomy and Cell Biology, Ann Arbor, USA
| | | | | |
Collapse
|
12
|
Raitiere MN, Garyfallou VT, Urbanski HF. Lesions in the bed nucleus of the stria terminalis, but not in the lateral septum, inhibit short-photoperiod-induced testicular regression in Syrian hamsters. Brain Res 1995; 705:159-67. [PMID: 8821746 DOI: 10.1016/0006-8993(95)01152-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The transfer of adult male hamsters from long days (LD) to short days (SD) (i.e. < 12 h of light per day) typically results in marked testicular regression and a decline in plasma testosterone concentrations. To help disclose key brain regions responsible for mediating this photoperiodic response male hamsters received either chemical (i.e. N-methyl-D-aspartate; NMDA) or radiofrequency current lesions in the bed nucleus of the stria terminalis (BNST), and were then exposed to SD for 15 or 12 weeks, respectively. Although body weights were similar between sham-lesioned controls and the NMDA-lesioned hamsters, the latter showed a significant attenuation of testicular regression; additionally, their plasma testosterone concentrations remained at typical LD levels. When radiofrequency current-lesioned hamsters were transferred from LD to SD they also failed to show significant signs of testicular regression, nor a decline in plasma testosterone concentrations, nor a complete arrest of spermatogenesis. In contrast, sham-lesioned controls or hamsters that were lesioned dorsally to the BNST at a site primarily involving the lateral septum all showed the expected degree of testicular regression, a decline in plasma testosterone concentrations, and complete arrest of spermatogenesis; body weights were similar in all of the experimental group. Taken together, these findings suggest that the BNST, a brain area traditionally not associated with reproductive function, may play an important role in mediating photoperiodic information to the neural circuits that control the reproductive axis.
Collapse
Affiliation(s)
- M N Raitiere
- Division of Neuroscience, Oregon Regional Primate Research Center, Beaverton 97006, USA
| | | | | |
Collapse
|
13
|
Pfeiffer CA, Johnston RE. Hormonal and behavioral responses of male hamsters to females and female odors: roles of olfaction, the vomeronasal system, and sexual experience. Physiol Behav 1994; 55:129-38. [PMID: 8140156 DOI: 10.1016/0031-9384(94)90020-5] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Removal of the vomeronasal organ eliminated androgen surges in male hamsters in response to female vaginal secretions in both sexually experienced and sexually naive males; lesions of the olfactory mucosa had no effect on such responses. Both lesions led to deficits in behavioral responses to vaginal secretions. In response to interactions with estrous females, in contrast, lesions of either system alone had no influence on androgen surges in males (either sexually experienced or naive). Lesions of both systems, however, eliminated androgen surges in sexually naive males but not sexually experienced males. These dual lesions eliminated male mating behavior, while lesions of either system alone had little influence on mating. There were no significant correlations in any experiment between level of behavioral responses and degree of change in androgen levels. Thus, we conclude that the vomeronasal system mediates androgen surges in response to female odors but is not necessary for such responses to females themselves. In sexually naive males the vomeronasal and olfactory systems together are necessary for androgen responses to females. Behavioral responses were influenced by lesions and by sexual experience. Lesions of both systems increased the latency to investigate vaginal secretions, and sexual experience decreased the latency and increased the duration of investigation. Lesions and experience also influenced male sexual performance.
Collapse
Affiliation(s)
- C A Pfeiffer
- Department of Psychology, Cornell University, Ithaca, NY 14853
| | | |
Collapse
|
14
|
Cooper HM, Parvopassu F, Herbin M, Magnin M. Neuroanatomical pathways linking vision and olfaction in mammals. Psychoneuroendocrinology 1994; 19:623-39. [PMID: 7938360 DOI: 10.1016/0306-4530(94)90046-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Retinal projections to several telencephalic structures have been demonstrated in a wide range of mammalian species following intraocular injections of tritiated amino acids and cholera toxin subunit-B conjugated to horseradish peroxidase. Since these regions are also innervated by olfactory fibers, we investigated the distribution of convergent projections using simultaneous injections of different anterograde tracers in the eye and olfactory bulbs. Convergent projections from the retina and from the olfactory bulbs were observed in the piriform cortex, olfactory tubercle, the cortical region of the medial amygdala, lateral hypothalamus, and the bed nucleus of the stria terminalis. A few retinal fibers also invade the nucleus of the lateral olfactory tract, the bed nucleus of the accessory olfactory bulb and the diagonal band of Broca. Injections of retrograde tracers in the medial amygdala, the bed nucleus or the lateral hypothalamus shows that the visuo-olfactory convergence mainly involves projections originating from the accessory olfactory bulb, and to a lesser extent from the ventromedial region of the main olfactory bulb. Fewer than 20 retinotelencephalic ganglion cells were identified in the retina, mainly located contralateral to the injection site. Ganglion cells were medium sized and possessed two long slender opposing dendrites. These retinal and olfactory projections could provide an anatomical substrate for the modulation of gonadotropin hormone levels and the olfactory influence on light mediated rhythms related to reproductive physiology.
Collapse
Affiliation(s)
- H M Cooper
- Cerveau et Vision, INSERM U-371, Bron, France
| | | | | | | |
Collapse
|
15
|
Pieper DR, Lobocki CA. Olfactory bulbectomy induces reproductive recrudescence in golden hamsters on short photoperiod. Neurosci Lett 1993; 155:227-9. [PMID: 8377953 DOI: 10.1016/0304-3940(93)90714-v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Olfactory bulbectomy results in a marked increase in gonadotropin secretion and prevents the reproductive regression associated with short photoperiod when the olfactory bulbectomy is done before exposure to the inhibitory photoperiod. The present study tested whether olfactory bulbectomy would offset the influence of short photoperiod if done after the reproductive system had regressed. Adult golden hamsters Mesocricetus auratus were divided into four groups: early sham (surgery at week-4); early olfactory bulbectomy (surgery at week-4); late sham (surgery at week 14) and late olfactory bulbectomy (surgery at week 14). At t = 0, all golden hamsters were placed in a short photoperiod (L:D 10:14). Early olfactory bulbectomy prevented testicular regression; the late olfactory bulbectomy group recrudesced much earlier than the sham groups. These results indicate that the tonic inhibitory influence of the olfactory bulbs is required for initiation of short photoperiod induced testicular regression and is also essential for the maintenance of the regressed state.
Collapse
Affiliation(s)
- D R Pieper
- Department of Physiology and Research, Providence Hospital, Southfield, MI 48037
| | | |
Collapse
|
16
|
Ruby NF, Zucker I, Licht P, Dark J. Olfactory bulb removal lengthens the period of circannual rhythms and disrupts hibernation in golden-mantled ground squirrels. Brain Res 1993; 608:1-6. [PMID: 8495334 DOI: 10.1016/0006-8993(93)90765-f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Removal of the olfactory bulbs lengthened the period of circannual rhythms (CARs) of body mass and plasma testosterone (T) concentrations in male golden-mantled ground squirrels, but did not otherwise alter their expression. The period of the CAR was approximately 2 months longer in bulbectomized than in sham-operated animals. Peak values of body mass and T were unaffected by bulbectomy. All neurologically intact, but only 50% of bulbectomized, squirrels displayed normal hibernation patterns. We conclude that the olfactory bulbs are not the site of essential circannual oscillators. Circannual reproductive and hibernation cycles of ground squirrels are less subject to modulation by the olfactory bulbs than are the corresponding rhythms of several non-circannual hamster species.
Collapse
Affiliation(s)
- N F Ruby
- Department of Psychology, University of California, Berkeley 94720
| | | | | | | |
Collapse
|
17
|
Pieper DR, Johnson KD, Lobocki CA. Unilateral but not bilateral olfactory bulbectomy inhibits body weight gain in hamsters. Physiol Behav 1992; 52:1151-4. [PMID: 1484874 DOI: 10.1016/0031-9384(92)90474-g] [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: 12/27/2022]
Abstract
The relation of the olfactory bulbs and photoperiod to the regulation of body weight was studied in male golden hamsters. Animals underwent sham operation, bilateral olfactory bulbectomy, or unilateral bulbectomy. They were left on long photoperiod for 5 weeks and then were transferred to short photoperiod for 11 weeks. The unilaterally olfactory bulbectomized hamsters gained less weight on long or short photoperiod than the sham operated group, while the bilaterally bulbectomized hamsters gained at least as much weight as the sham group. Thus, we report the novel finding that unilateral but not bilateral olfactory bulbectomy reduces body weight gain in male golden hamsters.
Collapse
Affiliation(s)
- D R Pieper
- Providence Hospital, Southfield, MI 48037
| | | | | |
Collapse
|
18
|
Babura LL, Sisk CL, Nunez AA. Photoperiodic regulation of prolactin release in male hamsters with hypothalamic knife cuts. Brain Res Bull 1992; 29:231-7. [PMID: 1525676 DOI: 10.1016/0361-9230(92)90031-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Horizontal knife cuts placed dorsal to the paraventricular nucleus (PVN) of the hypothalamus prevent testicular regression in hamsters kept in short days. We examined the effects of these cuts on the photoperiodic modulation of the postcastration rise in gonadotropins, as well as on the release of prolactin in castrated and gonadally intact animals. The cuts blocked the inhibitory effects of short daylengths on the postcastration rise in circulating levels of gonadotropins. However, the cuts did not prevent the reduction in prolactin levels induced by short daylengths in castrated and gonadally intact animals. We conclude that dorsal connections of the PVN are not required for transduction of photoperiodic information used to regulate prolactin release. The knife cuts may remove tonic inhibitory influences on the release of follicle-stimulating hormone and luteinizing hormone, and thus produce elevated gonadotropin levels that mask the effects of nonstimulatory photoperiods on testicular size.
Collapse
Affiliation(s)
- L L Babura
- Department of Psychology, Michigan State University, East Lansing 48824-1117
| | | | | |
Collapse
|
19
|
Carlson LL, Weaver DR, Reppert SM. Melatonin receptors and signal transduction during development in Siberian hamsters (Phodopus sungorus). BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1991; 59:83-8. [PMID: 1645629 DOI: 10.1016/0165-3806(91)90032-e] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Maternal melatonin communicates daylength information to the fetus in Siberian hamsters. Fetal sensitivity to melatonin declines near birth. In this report, we describe melatonin receptor distribution and a second messenger response to melatonin in Siberian hamsters during the perinatal period. The sites of high-affinity 2-[125I]iodomelatonin ([125I]MEL) binding were generally similar throughout the perinatal period. The non-hydrolyzable GTP analog, guanosine-5'-O-(3-thiotriphosphate) (100 microM) inhibited [125I]MEL binding at each age, suggesting the melatonin receptors are associated with guanine nucleotide binding proteins (G proteins). Furthermore, melatonin (10 nM) inhibited forskolin-stimulated cAMP accumulation in median eminence/pars tuberalis (ME/PT) explants as early as 4 days before birth, when sensitivity to melatonin in vivo is high. The cAMP regulatory system appeared disrupted on the day of birth, in that forskolin (10 microM) stimulation of cAMP accumulation was reduced, and melatonin did not inhibit cAMP accumulation stimulated by forskolin. A higher forskolin dose (100 microM) elevated cAMP levels more clearly on the day of birth, and melatonin inhibited forskolin-stimulated cAMP accumulation. These results suggest that the decreased physiological responsiveness to melatonin at the end of gestation may be due to alterations in the cAMP regulatory system.
Collapse
Affiliation(s)
- L L Carlson
- Laboratory of Developmental Chronobiology, Massachusetts General Hospital, Boston 02114
| | | | | |
Collapse
|
20
|
Badura LL, Sisk CL, Nunez AA. Effects of photoperiod and hypothalamic knife cuts on the timing of FSH surges in hamsters. Brain Res Bull 1991; 26:313-6. [PMID: 1901507 DOI: 10.1016/0361-9230(91)90244-e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The timing of the proestrous surge of follicle-stimulating hormone (FSH) was examined in female hamsters with hypothalamic knife cuts that prevented reproductive responses to photoperiod. All animals received either a horizontal knife cut aimed between the suprachiasmatic nuclei (SCN) and the paraventricular nuclei (PVN), or sham surgery, and were housed in long (16 h of light/24 h) or short (6 h of light/24 h) photoperiods. Following exposure to either photo-period for 11-12 weeks, a subset of the animals was fitted with an indwelling jugular cannula. Blood samples were taken hourly over a 24-h period and plasma levels of FSH were determined by RIA. Knife cuts placed ventral to or through the ventral portions of the PVN prevented short day-induced anestrus. On the day of proestrus, peak elevations of FSH in cycling animals with knife cuts in both photoperiods, as well as in sham-operated females in long days, occurred 4-5 h before lights out. In contrast, sham-operated anestrous females in short days showed peak elevations of FSH approximately 3-4 h after lights out. The present results support the view that neural connections between the SCN and the PVN mediate the effects of short days on reproductive physiology, including changes in the timing of the FSH surge.
Collapse
Affiliation(s)
- L L Badura
- Psychology Department, Michigan State University, East Lansing 48824
| | | | | |
Collapse
|
21
|
Pieper DR, Lobocki CA, Thompson M, Subramanian MG. The olfactory bulbs enhance reproductive hormone secretion in male rats on long or short photoperiod. J Neuroendocrinol 1990; 2:717-23. [PMID: 19215410 DOI: 10.1111/j.1365-2826.1990.tb00469.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Abstract Unlike seasonally breeding species such as the Syrian hamster, Sprague-Dawley laboratory rats do not normally respond to short photoperiod (6L18D) with reproductive regression. However, removal of the olfactory bulbs (BX) unmasks a photoperiodic response in pre-pubertal rats so that blinding or short photoperiod results in an inhibition of reproductive hormone secretion and/or a delay in pubertal development. This is apparently mediated by pineal melatonin which inhibits gonadotropin and/or prolactin secretion, but the mechanism by which BX facilitates the response to photoperiod is not clear. Experiment I was performed to determine serum levels of reproductive hormones at frequent intervals following BX and/or maintenance on short days. Twenty-three-day old male rats were BX or underwent sham BX (SH). They were thereafter maintained on a 14L:10D (long photoperiod) or 6L:18D photoperiod for the duration of the study. At 6 weeks following surgery, BX rats on either photoperiod had smaller testes than the SH groups. At week 8, the BX group on 6L:18D had smaller testes than the other three groups. There were transient reductions in serum luteinizing hormone and follicle-stimulating hormone in the BX rats on short photoperiod, but there were prolonged effects of BX decreasing prolactin levels in rats on long or short photoperiod. In SH rats, testosterone was elevated for weeks 6 through 10 of the study, and BX blocked this increase. Experiment II was performed to determine whether BX alters testosterone feedback on gonadotropin secretion. Twenty-three-day old male rats were BX or underwent SH operation and were then returned to a room on 14L10D. Six to 8 weeks later, all animals were castrated and placed on 6L18D or returned to 14L:10D. Eight weeks following castration, the rats were implanted with Silastic capsules containing 0, 10, 20 or 40mm testosterone. The post-castration increase in serum luteinizing hormone and follicle-stimulating hormone was lower in the BX than SH rats. In long photoperiod, serum luteinizing hormone and follicle-stimulating hormone were often lower in the BX rats receiving no testosterone replacement or lower doses of testosterone than in the SH group receiving similar capsules. Maintenance on short photoperiod increased the responsiveness to testosterone so that even the rats receiving low doses of testosterone had very low luteinizing hormone and follicle-stimulating hormone levels whether they were SH or BX. In summary, BX rats on long or short photoperiod had lower serum prolactin and testosterone levels than the comparable SH group and BX inhibited the post-castration increase in gonadotropin secretion. The data therefore suggest that the olfactory bulbs tonically enhance reproductive hormone secretion (especially around the time of pubertal development).
Collapse
Affiliation(s)
- D R Pieper
- Providence Hospital, Department of Physiology, Southfield, Michigan 48037, USA
| | | | | | | |
Collapse
|
22
|
Pieper DR, Lobocki CA, Thompson M, Subramanian MG. The olfactory bulbs tonically inhibit serum gonadotropin and prolactin levels in male hamsters on long or short photoperiod. J Neuroendocrinol 1990; 2:707-15. [PMID: 19215409 DOI: 10.1111/j.1365-2826.1990.tb00468.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Abstract Bilateral removal of the olfactory bulbs (BX) inhibits the testicular regression associated with maintenance of golden hamsters on short photoperiod (10L:14D). The present study was done to examine the reproductive endocrine changes following BX of hamsters, to test whether BX increases gonadotropin secretion by enhancing the rate of metabolism of peripheral testosterone, and to determine whether BX inhibits the response to photoperiod by blocking chemosensory signals from conspecifics. BX resulted in a marked increase in tonic serum gonadotropin levels in pre-pubertal (23 days old) and adult hamsters maintained on long photoperiod (14L:10D). Maintenance on 10L14D inhibited gonadotropin secretion in BX hamsters, but this only reduced the previously elevated levels to those of the sham group on stimulatory photoperiod, and the testes therefore remained large. BX hamsters on 10L:14D had a higher post-castration increase in serum luteinizing hormone than sham-operated hamsters. Following testosterone replacement (20 mm Silastic capsules), BX animals had lower serum testosterone and higher serum follicle- stimulating hormone levels than the sham group. BX hamsters had a shorter mean half-time for disappearance of testosterone from serum following removal of the capsule, but some animals in the sham group also metabolized testosterone rapidly. Isolation in cages receiving air filtered to remove pheromonal type molecules did not affect the rate or degree of testicular regression in response to short days. We conclude that the olfactory bulbs tonically inhibit gonadotropin release in golden hamsters on long or short photoperiod. The olfactory bulbs may facilitate the negative feedback of testosterone and may inhibit testosterone metabolism, but there were also steroid-independent effects. The influence of the olfactory bulbs on the hamsters' response to short days is apparently not related to chemosensory information from other hamsters.
Collapse
Affiliation(s)
- D R Pieper
- Providence Hospital, Department of Physiology, Southfield, Michigan 48037, USA
| | | | | | | |
Collapse
|
23
|
Possidente B, Lumia AR, McGinnis MY, Teicher MH, deLemos E, Sterner L, Deros L. Olfactory bulb control of circadian activity rhythm in mice. Brain Res 1990; 513:325-8. [PMID: 2350703 DOI: 10.1016/0006-8993(90)90475-q] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ablation of mouse olfactory bulbs lengthened the circadian period of wheel-running activity by 43 min and delayed the onset of entrained activity by 108 min. A transient increase in activity during the light phase of the 12:12 h light-dark photoperiod also occurred following surgery. These disruptions suggest that olfactory systems can modulate mammalian circadian rhythms.
Collapse
Affiliation(s)
- B Possidente
- Biopsychology Program, Skidmore College, Saratoga Springs, NY 12866
| | | | | | | | | | | | | |
Collapse
|
24
|
Smale L, Morin LP. Photoperiodic responsiveness of hamsters with lesions of the lateral geniculate nucleus is related to hippocampal damage. Brain Res Bull 1990; 24:185-90. [PMID: 2322852 DOI: 10.1016/0361-9230(90)90204-d] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We tested the hypothesis that the geniculohypothalamic tract is important for hamster photoperiodism. Adult male hamsters, maintained in a long photoperiod (LD 14:10), received either large bilateral neurotoxic lesions of the lateral geniculate nucleus (LGN) or sham lesions. One week later, half of the animals from each group were transferred to a short photoperiod (LD 8:16) where they were maintained for 15 weeks. Most lesions effectively destroyed the intergeniculate leaflet (IGL) and much of the lateral geniculate complex. They also caused substantial damage to the overlying hippocampus. The lesions had no effect on long-day animals, but significantly reduced the extent of testicular regression during short photoperiod exposure. This effect, however, appeared to be the result of hippocampal, rather than geniculate, damage. Four individuals with complete IGL lesions, but minimal hippocampal damage, underwent a pattern of regression that was indistinguishable from controls. Body weight was increased by lesions in short-day, but not long-day, animals. This effect was not related to the extent of hippocampal damage. We conclude that geniculate input to the suprachiasmatic nuclei is not essential for hamster photoperiodism and that hippocampal damage may modify the effect of short daylengths on testes size.
Collapse
Affiliation(s)
- L Smale
- Department of Psychiatry, State University of New York, Stony Brook 11794
| | | |
Collapse
|
25
|
Tubbiola ML, Nock B, Bittman EL. Photoperiodic changes in opiate binding and their functional implications in golden hamsters. Brain Res 1989; 503:91-9. [PMID: 2611662 DOI: 10.1016/0006-8993(89)91708-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Daylength modulates gonadotropin secretion, gonadal steroid hormone feedback, sexual behavior and body weight in male golden hamsters. Endogenous opiates regulate each of these phenomena, and the ability of opiate receptor blockade to elevate serum LH secretion is photoperiod-dependent. We used in vitro autoradiography to localize and quantify effects of daylength in golden hamsters. Hamsters were exposed to stimulatory (14 h light: 10 h dark) or inhibitory (10 h light: 14 h dark) photoperiods for 10 weeks before specific [3H]naloxone binding was assessed. Short days significantly decreased binding in medial amygdala and the intercalated amygdaloid nucleus. This effect was reversed by superior cervical ganglionectomy. No significant effects of daylength were observed in other amygdaloid, hypothalamic or preoptic areas. Lesions of the medial amygdala decreased copulatory behavior, short day-induced weight loss, and anogenital chemoinvestigation but did not affect gonadal regression or other forms of chemoinvestigation. These lesions facilitated testosterone's negative feedback on luteinizing hormone in long days but did not interfere with the potentiation of negative feedback by short days.
Collapse
Affiliation(s)
- M L Tubbiola
- Department of Zoology, University of Massachusetts, Amherst 01003
| | | | | |
Collapse
|
26
|
Pieper DR, Newman SW, Lobocki CA, Gogola G. Bilateral transection of the lateral olfactory tract but not removal of the vomeronasal organs inhibits short-photoperiod-induced testicular regression in golden hamsters. Brain Res 1989; 485:382-90. [PMID: 2655825 DOI: 10.1016/0006-8993(89)90582-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
It is now known that removal of the olfactory bulbs increases basal gonadotropin secretion and prevents short-photoperiod-induced testicular regression in Syrian hamsters. The experiments described in the present paper were an attempt to determine which neuronal systems associated with the olfactory bulbs are responsible for this influence on the reproductive neuroendocrine axis. In the first experiment, removal of the vomeronasal organ failed to influence gonadotropin secretion or testes weight in hamsters on long or short photoperiod, suggesting that the vomeronasal-accessory olfactory pathway is not individually responsible for the effect of the olfactory bulbs on gonadotropin secretion. In the second experiment, bilateral transection of the lateral olfactory tracts (LOT) did prevent short-photoperiod-induced testicular regression and the associated decrease in gonadotropin secretion. Since the nervus terminalis is confined to the surface of the medical olfactory bulb pathway, the results of LOT transection indicate that the nervus terminalis, which itself contains gonadotropin releasing hormone, does not mediate the influence of the olfactory bulbs on gonadotropin secretion. These results further suggest that the olfactory bulb influence on gonadotropin secretion is due to neural connections to the pyriform cortex, entorhinal cortex or amygdala.
Collapse
Affiliation(s)
- D R Pieper
- Providence Hospital, Department of Physiology, Southfield, MI 48037
| | | | | | | |
Collapse
|
27
|
Badura LL, Kelly KK, Nunez AA. Knife cuts lateral but not dorsal to the hypothalamic paraventricular nucleus abolish gonadal responses to photoperiod in female hamsters (Mesocricetus auratus). J Biol Rhythms 1989; 4:79-91. [PMID: 2519582 DOI: 10.1177/074873048900400106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Horizontal and parasagittal knife cuts in the hypothalamus of female hamsters (Mesocricetus auratus) were employed to investigate the neural pathways that mediate gonadal responses to photoperiod. Bilateral horizontal knife cuts placed dorsal to the paraventricular nucleus (PVN) did not prevent short-day-induced acyclicity and uterine regression. On the other hand, regardless of photoperiod, animals with bilateral parasagittal knife cuts placed lateral to the PVN continued to exhibit regular 4-day estrous cycles and stimulated uteri. Thus, parasagittal cuts prevented the effects of short days on reproductive physiology. This finding suggests that the lateral efferent projections from the PVN represent an important component of the neural pathway mediating reproductive photoperiodism in female hamsters.
Collapse
Affiliation(s)
- L L Badura
- Psychology Department, Michigan State University, East Lansing 48824-1117
| | | | | |
Collapse
|
28
|
Smale L, Cassone VM, Moore RY, Morin LP. Paraventricular nucleus projections mediating pineal melatonin and gonadal responses to photoperiod in the hamster. Brain Res Bull 1989; 22:263-9. [PMID: 2706538 DOI: 10.1016/0361-9230(89)90052-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Knife cuts were placed around the paraventricular nucleus of the hypothalamus (PVN) in order to identify the pathways mediating photoperiodism and pineal melatonin production in male golden hamsters. Cuts in the coronal plane caudal to the PVN, have no effect on photoperiodic control of the testes unless they actually damage the PVN. Bilateral parasagittal cuts at the medial border of the lateral hypothalamus block short photoperiod-induced gonadal regression. Nighttime levels of pineal melatonin are reduced by these cuts, but unaffected by caudal cuts. Projections from the lateral PVN region descending towards the spinal cord appear to be critical for the control of pineal melatonin production and the control of the testicular function by short photoperiod.
Collapse
Affiliation(s)
- L Smale
- Department of Psychiatry, State University of New York, Stony Brook 11794
| | | | | | | |
Collapse
|
29
|
Buzzell GR. Studies on the effects of the pineal hormone melatonin on an androgen-insensitive rat prostatic adenocarcinoma, the Dunning R 3327 HIF tumor. J Neural Transm (Vienna) 1988; 72:131-40. [PMID: 3385424 DOI: 10.1007/bf01250236] [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: 01/05/2023]
Abstract
The effects of the pineal indole melatonin on a transplantable androgen-insensitive fast-growing rat prostatic adenocarcinoma, the Dunning R 3327 HIF tumor, were examined. Afternoon injections of melatonin given to intact male rats enhanced tumor growth, while leading to a reduction in the weights of gonads and dorsal and ventral prostates. In anosmic hosts, this treatment had no effect on tumor growth or reproductive organ size. In castrated anosmic hosts, melatonin injections led to reductions in the growth of tumors, when compared with those in castrated hosts. Continuously available melatonin, in beeswax pellets, had no effect on growth of these tumors. These results are discussed in relation to the anticancer effects of melatonin and the effects of tumors on endogenous melatonin rhythms.
Collapse
Affiliation(s)
- G R Buzzell
- Department of Anatomy and Cell Biology, University of Alberta, Edmonton, Canada
| |
Collapse
|
30
|
Pieper DR, Reiter RJ, Unthank PD, Addy JF. Evidence that olfactory bulbectomy does not influence testicular regression in golden hamsters on short photoperiod by altering pineal melatonin production. J Comp Physiol B 1988; 158:301-5. [PMID: 3142942 DOI: 10.1007/bf00695328] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A recent study has shown that olfactory bulbectomy (BX) will prevent reproductive regression associated with short photoperiod in male golden hamsters. The results of experiments reported in this paper show that bulbectomized hamsters on long or short photoperiod still show a large nocturnal elevation in pineal melatonin production and that BX inhibits the reproductive regression induced by exogenous melatonin in pinealectomized hamsters. The data therefore indicate that BX does not inhibit short photoperiod induced testicular regression by altering melatonin secretion.
Collapse
Affiliation(s)
- D R Pieper
- Department of Physiology, Providence Hospital, Southfield, Michigan 48037
| | | | | | | |
Collapse
|
31
|
Macrides F, Schoenfeld TA, Clancy AN, Kumar MS, Kream RM. Hormones and neurotransmitters in the mammalian olfactory system. Ann N Y Acad Sci 1987; 519:150-64. [PMID: 2452592 DOI: 10.1111/j.1749-6632.1987.tb36294.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- F Macrides
- Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545
| | | | | | | | | |
Collapse
|