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The amplitudes of miniature excitatory postsynaptic currents in NTS neurons from female rats vary as a function of the estrus cycle
Author(s) -
Jia Shuping W,
MIfflin Steve
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.561.6
Subject(s) - estrous cycle , excitatory postsynaptic potential , postsynaptic current , medicine , endocrinology , postsynaptic potential , biology , glutamatergic , neurotransmission , inhibitory postsynaptic potential , andrology , glutamate receptor , receptor
Very little information exists regarding how glutamatergic transmission within the nucleus of the solitary tract (NTS) of females might vary as a function of the estrus cycle. Spontaneous miniature excitatory postsynaptic currents (mEPSCs) were recorded in caudal NTS slices (250μM thick) superfused with TTX (1 um) and gabazine (25 um) under voltage clamp. Female rats were studied at different stages of the estrus cycle determined by vaginal smear and the number of neurons studied at each stage of the estrus cycle is as follows: estrus n=16; metestrus n=14; diestrus n=22. Male rats (n=33) were also studied for comparison. All mEPSCs were blocked by superfusion of the slice with CNQX (10 um). The amplitude of mEPSCs was significantly lower in diestrus (16.53 ± 1.01 pA) compared to estrus (23.30 ± 2.12 pA), metestrus (19.95 ± 1.13 pA), and males (20.49 ± 1.29 pA) (all p<0.035). The frequency of mEPSCs did not vary across the estrus cycle in females however mEPSC frequency was significantly lower in males (2.74 ± 0.28 Hz) compared to estrus (4.23 ± 0.63 Hz, p=.010) and metestrus (4.34 ± 0.61 Hz, p=.005). The frequency of mEPSCs did not differ between males and females in diestrus (3.68 ± 0.54 Hz, p=.085). mEPSC rise time did not differ between the 3 female groups and males (all p>.111). mEPSC decay time was significantly greater in estrus (9.00 ± 0.75 ms) compared to males (7.50 ± 0.39 ms, p=.038) but decay time during estrus did not differ from that in metestrus (7.58 ± 0.61 ms) and diestrus (7.59 ± 0.41 ms) (both p>.088). These results suggest that glutamatergic transmission in NTS neurons in female rats can vary as a function of the estrus cycle. During diestrus plasma estrogen levels are rising and during diestrus we observed mEPSCs with amplitudes lower than during other phases of the estrus cycle or in males. This suggests that estrogen may have a post‐synaptic effect that reduces NTS neuronal responses to glutamatergic inputs. Preliminary whole cell recordings from 3 NTS neurons in a brain slice from estrogen receptor alpha‐td tomato reporter mice lend support to this interpretation as superfusion of the slice with 100 nm 17β‐estradiol reversibly reduced mEPSC amplitude from 19–29%. Support or Funding Information This work was supported by HL088052 This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .