4 Matching Annotations
  1. May 2020
    1. While somewhat modest in size, the literature on chronic tolerance to nicotine in humans is reasonably consistent in showing clear evidence of tolerance to subjective mood effects but little or no tolerance to cardiovascular, performance or other nicotine effects

      This is what I'd expect for tobacco, but it tells me little about nicotine. Most of the subjective effects are not from tobacco, so It's still plausible that nicotine does not develop tolerance. Indeed, the effects that don't go away are the effects expected from nicotine.

    1. Hippocampal size of nonusers reflects a direct relationship to memory function; the smaller the hippocampus, the poorer the memory function. Individuals who use marijuana and tobacco show an inverse relationship, i.e., the smaller the hippocampus size, the greater memory the function. Furthermore the number of nicotine cigarettes smoked per day in the marijuana and nicotine using group appears to be related to the severity of hippocampal shrinkage. The greater the number of cigarettes smoked per day, the smaller the hippocampal volume and the greater the memory performance. There were no significant associations between hippocampal size and memory performance in individuals who only use tobacco or only use marijuana.

      They mention abstainers below. It appears that they are saying that there is memory improvement compared to complete non-smokers. Will need to check actual study. Note that my interest in nicotine is confounded by the use of tobacco.

      Edit: eyeballing the graphs, it appears that the tobacco group did the best, while the marijuana plus tobacco group did the worst. Given the small sample size and high variability, these are not statistically significant. Nonetheless, that suggests that marijuana never benefits memory. Edit: eyeballing the graphs, it appears the tobacco group did the best, while the marijuana plus tobacco group performed worst. Given the small sample size and high variability, these results are not statistically significant. Nonetheless, it suggests that marijuana is never a benefit to memory.

    1. 16S sequencing showed that nicotine perturbed bacterial diversity and community composition of gut microbiota more pronouncedly in HFD mice.

      Note that nicotine by itself had minimal impact on the microbiome. Nicotine speeds up transit through the intestine. Thus, the reason nicotine plus a high fat diet was detrimental is likely that nicotine is increasing the throughput of harmful prebiotics (e.g. protein in particular). When lots of fiber and resistant starch is present (will need to see if they provide this info for their diets), then nicotine mostly just carries it to the small intestine faster (and possibly reduces fermentation time).

      Given that opioids have a negative effect on the microbiome, I was expecting nicotine to have a positive effect. Perhaps it would have a positive effect were there more resistant starch in the diet.

  2. Mar 2018
    1. Nicotine is composed of a pyridine ring and a pyrrolidine ring, synthesized from two separate branches as demonstrated in Figure S1

      This is interesting!