Discussion in 'Physiology and Biology' started by neurobadger, Nov 13, 2011.
What studies have been done on the cellular aspects of octopus senescence?
Do we have no idea what actually happens to the octopus brain when it senesces?
To my knowledge, there are only two somewhat recent papers on senescence (in octopus).
This area is wide open if you want to investigate more.
There was one on the squid Onykia (Moroteuthis) ingens, by George Jackson and Phil Mladenov but it focused more on changes to mantle tissue (which can be quite extreme in this species!)
Jackson, G.D.; Mladenov, P.V. 1994. Terminal spawning in the deepwater squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae). Journal of Zoology, London 234, 189−201.
This is not quite on point, but is related. The paper (from 1998) is free:
It shows that one group of squid, whose life span is measured in a few months, has radically different growth rates and life spans (almost 2 to 1 difference) depending on the temperature. The summer lifespan was 3-4 months, winter squid of this species lived about 6 months.
Of particular interest was the discussion of how, and when, the squid grew compared to fish. They thought at first that the growth curve tapered off, but this was an artifact of measuring growth data independent of season. Once they corrected for that, it became obvious that the growth was continuous throughout their lives, and "it becomes apparent that growth is nonasymptotic; squids that hatched during warmer seasons had faster growth rates and shorter lives."
There was some discussion of growth at the cellular level:
But this quote is the closest to the kind of information being sought in this thread:
That's the same effect referred to by the paper Jean describes above.
While there isn't a lot of info out there specific to octopus, there is a substantial (although not extensive) literature on cellular changes during end-stage reproduction (which is closely temporally-linked to senescence in some molluscs, including most cephs). If you are seeking a starting point, this might be good to explore. There is also a lot of work on aging in cuttlefish by Raymond Chichery's group - if you haven;t seen them you should take a look at these - they might give you some ideas of interesting things to look at on the cellular and sub-cellular level.
In vitro evidence and age-related changes for nicotinic but not muscarinic acetylcholine receptors in the central nervous system of Sepia officinalis: Cécile Bellanger, Marie-Pierre Halmb, François Dauphin, Raymond Chichery
Variations of the lipid constituents in the central nervous system of the cuttlefish (Sepia officinalis) during aging. E Dumont, M Chichery, A Nouvelot, R Chichery
Physiological aspects of post-reproductive senescence in Octopus vulgaris. RW Tait - 1986
Behavioural and neurohistological changes in aging Sepia. M P Chichery and R Chichery
Effect of aging on manipulative behavior in the cuttlefish, sepia. Halm MP, Agin V, Chichery MP, Chichery R.
Learning performances and aging in cuttlefish (Sepia officinalis). Chichery R, Chichery MP.
Separate names with a comma.