Gonadal steroids are known to influence hippocampal physiology in adulthood. It is presently unknown whether gonadal the morphology of neurons adult intact rat brain. In order determine female sex hormones adult, we performed Golgi impregnation on brains from ovariectomized rats and which received estradiol or progesterone replacement. Removal circulating by ovariectomy resulted a profound decrease dendritic spine density CA1 pyramidal cells hippocampus. Estradiol replacement prevented...

We have used Golgi-impregnated tissue to demonstrate that apical dendritic spine density in CA1 hippocampal pyramidal cells undergoes a cyclic fluctuation as estradiol and progesterone levels vary across the estrous cycle adult female rat. observed 30% decrease over 24-hr period between late proestrus estrus phases of cycle. Spine then appears back values several days. In contrast, no significant changes occur CA3 or dentate gyrus granule cells. These results rapid ongoing plasticity...

We have previously shown that the density of dendritic spines on hippocampal CA1 pyramidal cells is dependent circulating estradiol and progesterone fluctuates naturally during 5 day estrous cycle in adult rat. To date, however, no detailed characterization roles these hormones play regulation spine has been made. In order to determine time courses extent effects density, we analyzed lateral branches apical tree Golgi-impregnated several experiments. summary, our findings included following:...

We have found that the density of synapses in stratum radiatum hippocampal CA1 region adult female rat is sensitive to estradiol manipulation and fluctuates naturally as levels ovarian steroids vary during 5 d estrous cycle. In both cases, low are correlated with lower synapse density, while high a higher synapses. These synaptic changes occur very rapidly within approximately 24 hr between proestrus estrus stages cycle, we observe 32% decrease Synapse then appears cycle back values over...

Previous studies have shown that estradiol induces new dendritic spines and synapses on hippocampal CA1 pyramidal cells. We assessed the consequences of estradiol-induced cell intrinsic synaptic electrophysiological properties. Hippocampal slices were prepared from ovariectomized rats treated with either or oil vehicle. cells recorded injected biocytin to visualize spines. The association spine density parameters for each was then tested using linear regression analysis. found a negative...

In the adult female rat, densities of dendritic spines and synapses on hippocampal CA1 pyramidal cells are dependent upon ovarian steroid estradiol; moreover, spine synapse density fluctuate naturally as levels vary across estrous cycle. To determine whether effects estradiol require activation specific neurotransmitter systems, we have treated animals concurrently with one four selective receptor antagonists: MK 801, a noncompetitive NMDA antagonist; CGP 43487, competitive NBQX, an AMPA or...

The rat dentate gyrus is unusual among mammalian brain regions in that it shows cell birth well into adulthood. During development, regulated by adrenal steroids. However, presently unknown whether division the adult also mediated these same factors. In order to determine this case, we combined adrenalectomy, with or without corticosterone (CORT) replacement, and 3H-thymidine autoradiography, Nissl staining, immunohistochemistry for glial markers vimentin fibrillary acidic protein (GFAP) as...

Estradiol (E2) acutely potentiates glutamatergic synaptic transmission in the hippocampus of both male and female rats. Here, we investigated whether E2-induced potentiation occurs via presynaptic and/or postsynaptic mechanisms which estrogen receptors (ERs) mediate E2's effects each sex. Whole-cell voltage-clamp recordings mEPSCs CA1 pyramidal neurons showed that E2 increases mEPSC frequency amplitude within minutes, but often different cells. This indicated are involved, they occur largely...

The recently implemented National Institutes of Health policy requiring that grant applicants consider sex as a biological variable in the design basic and preclinical animal research studies has prompted considerable discussion within neuroscience community. Here, we present reasons to be optimistic this new will valuable for neuroscience, suggest some ways neuroscientists think about incorporating their research.

Abstract The rat dentate gyrus undergoes a period of naturally occurring cell death during the first postnatal week. In adult rat, removal circulating adrenal steroids by adrenalectomy is followed massive in granule layer, thus raising possibility that developmental results from low levels these hormones. Interestingly, two weeks life termed stress hyporesponsive period, are characterized very steroids. order to determine whether enable occur gyrus, we examined density pyknotic and healthy...

Neurons in the adult rat ventromedial hypothalamic nucleus (VMN, 4–6 neurons per brain; 3–7 brains group) were studied under various hormonal conditions using single-section Golgi impregnation technique. Intact rats of both sexes and ovariectomized females treated with oil, estrogen or progesterone used. Golgi-impregnated VMN analyzed to determine possible differences cell body size, number primary dendrites, dendritic branchpoints spine density. The only significant found In given there...

Dendritic spines are sites of the vast majority excitatory synaptic input to hippocampal CA1 pyramidal cells. Estrogen has been shown increase density dendritic on cell dendrites in adult female rats. In parallel with increased spine density, estrogen also number synapses formed multiple synapse boutons (MSBs). These findings suggest that estrogen-induced form contacts preexisting presynaptic boutons, transforming some previously single (SSBs) into MSBs. The goal current study was determine...

Previous studies have focused considerable attention on the effects of estrogen excitatory synaptic input to hippocampal CA1 pyramidal cells. Estrogen increases density dendritic spines and synapses cells sensitivity these input. Little is known, however, about inhibitory We used immunohistochemistry for glutamic acid decarboxylase whole-cell voltage-clamp recording IPSCs EPSCs at multiple time points after treatment (1) investigate regulation inhibition in (2) evaluate how affects...

The effect of estradiol to increase the density dendritic spines and axospinous synapses on hippocampal CA1 pyramidal cells in adult female rat has been well-documented. However, presynaptic involvement this process synapse elimination formation is unknown. To address issue, we have reconstructed 410 complete boutons through coded serial electron micrographs stratum radiatum determine the: (1) frequency multiple (MSB) vs. single (SSB) boutons; (2) number synaptic contacts per MSB; (3) bouton...