Here we see that estrogen causes increase in 5HT2A receptors. In premenstrual syndrome, emotional dysphoria is noted as the estrogen levels drop right before period. As estrogen levels increase again, the mood improves. So here it appears that 5HT2A could be related to N trait with its more exuberant and happier mood state.
Males don't have much estrogen naturally so are they less happier than females and could this be related to the less active N trait in males?
The debate will continue.