{'fraction_non_alphanumeric': 0.03480113636363636, 'fraction_numerical': 0.01775568181818182, 'mean_word_length': 4.704453441295547, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Association of different susceptibilities to morphine with the expression of 5-HTT and 5-HT1AR mRNA in brain regions of SD rats.

OBJECTIVE
To investigate the possible mechanism for the different CPP susceptibilities.


METHODS
Using a conditioned place preference (CPP) model, rats were selected into high and low preference groups. Using in situ hybridization, we examined the mRNA expression of 5-hydroxytryptamine transporter (5-HTT) and 5-hydroxytryptamine 1A receptor (5-HT1AR) in 3 crucial regions in addiction, namely the ventral tegmental area (VTA), the nucleus accumbens (NAc), and the medial prefrontal cortex (mPFC), during the dependence and withdrawal.


RESULTS
During dependence state, the expression of 5-HTT mRNA in each of the regions in the high preference group was significantly lower than that of the low preference group, while higher expression of 5-HT1AR mRNA in each of the regions in the high preference group than that of the low preference group was found (P < 0.05). During withdrawal state, the expression of 5-HTT mRNA in each of the regions in high preference group was significantly higher than that of the low preference group, while lower expression of 5-HT1AR mRNA in each of the regions in the high preference group than that of the low preference group was found (P < 0.05).


CONCLUSION
5-HTT and 5-HT1AR may play a role in differences in susceptibility to morphine.