Sexually dimorphic regulation of NK-1 receptor-mediated electrophysiological responses in vagal primary afferent neurons (original) (raw)

2000, Journal of neurophysiology

Neurons can display sexual dimorphism in receptor expression, neurotransmitter release, and synaptic plasticity. We have detected sexual dimorphism in functional tachykinin receptors in vagal afferents (nodose ganglion neurons, NGNs) by studying the effects of hormonal variation on the depolarizing actions of substance P (SP) in female guinea pig NGNs. Using conventional "sharp" microelectrode recording plus measurement of serum 17beta-estradiol values, we examined SP responses in NGNs isolated from 1) ovariectomized females (OVX), 2) OVX females treated with 17beta-estradiol (OVX + E2), 3) pregnant females, and 4) males. Depending on various manipulations, 19-41% female NGNs were depolarized (16 +/- 1.1 mV, mean +/- SE) by 100 nM SP acting through NK-1 receptors. The NGNs of OVX + E2 females (41%, 15/37; 17 +/- 2.1 mV) and pregnant females (41%, 32/79; 16 +/- 1.7 mV) were more likely to respond to SP than those of control males (P < 0.001). The percentage of SP-sensiti...