Behavioral decay in aging male C. elegans correlates with increased cell excitability

Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843-3258, USA.
Neurobiology of aging (Impact Factor: 5.01). 01/2012; 33(7):1483.e5-23. DOI: 10.1016/j.neurobiolaging.2011.12.016
Source: PubMed


Deteriorative changes in behavioral functions are natural processes that accompany aging. In advanced aged C. elegans nematodes, gross decline in general behaviors, such as locomotion and feeding, is correlated with degeneration of muscle structure and contractile function. In this study, we characterized the age-related changes in C. elegans male mating behavior to determine possible causes that ultimately lead to age-related muscle frailty. Unlike the kinetics of general behavioral decline, we found that mating behavior deteriorates early in adulthood, with no obvious muscle fiber disorganization or sperm dysfunction. Through direct mating behavior observations, Ca(2+) imaging, and pharmacological tests, we found that the muscular components used for mating become more excitable as the males age. Interestingly, manipulating either the expression of acetylcholine receptor (AChR) genes or dietary-mediated ether-a-go-go family K(+) channel function can reduce the muscle excitability of older males and concurrently improve mating behavior, suggesting a correlation between these biological processes.

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    • "Until recently, it was thought that C. elegans neurons did not show age-related morphological decline at either a cellular or subcellular level, because while other tissues, such as skin and muscle, deteriorate with age (Garigan et al., 2002), neurons remained surprisingly intact (Herndon et al., 2002). These data seem counterintuitive, considering multiple sensory behaviors as well as motility decline with age in C. elegans (Glenn et al., 2004; Murakami et al., 2005; Hsu et al., 2009; Kauffman et al., 2010; Guo et al., 2012) and changes in dendritic spines and synapse number with age have been observed in other organisms, including non-human primates and rats (reviewed in Burke and Barnes, 2006; Morrison and Baxter , 2012). Due to this incongruity, recent work has again tested the integrity of neurons and found that while neuronal cell bodies stay intact, neuronal processes, subcellular structures (Pan et al., 2011; Tank et al., 2011; Toth et al., 2012), and neuronal activity (Chokshi et al., 2010; Mulcahy et al., 2012) all show age-dependent changes. "
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