TY - JOUR
T1 - Dopamine/BDNF loss underscores narcosis cognitive impairment in divers
T2 - a proof of concept in a dry condition
AU - Bosco, Gerardo
AU - Giacon, Tommaso Antonio
AU - Paolocci, Nazareno
AU - Vezzoli, Alessandra
AU - Noce, Cinzia Della
AU - Paganini, Matteo
AU - Agrimi, Jacopo
AU - Garetto, Giacomo
AU - Cialoni, Danilo
AU - D’Alessandro, Natalie
AU - Camporesi, Enrico M.
AU - Mrakic-Sposta, Simona
N1 - Funding Information:
The authors would like to thank FIPSAS (Federazione Italiana Pesca Sportiva e Attività Subacquee, Rome Italy), Centro di Medicina Iperbarica ATIP, Padova, Italy, for supply of the hyperbaric chamber, Italy, and for the kind technical assistance of A. Fontana. The authors would like to thank also all the divers for participating in this study: A.Z.; L.B.; A.M.; M.G.; M.T.; G.G.
Funding Information:
Open access funding provided by Università degli Studi di Padova within the CRUI-CARE Agreement. This study was part of the "BIRD 2020" project, funded by the DSB-University of Padova and the E-Heart project founded by the Dan Europe Foundation. N.P. is funded by the National Institute of Health (R01 HL1369180).
Publisher Copyright:
© 2022, The Author(s).
PY - 2023/1
Y1 - 2023/1
N2 - Purpose: Divers can experience cognitive impairment due to inert gas narcosis (IGN) at depth. Brain-derived neurotrophic factor (BDNF) rules neuronal connectivity/metabolism to maintain cognitive function and protect tissues against oxidative stress (OxS). Dopamine and glutamate enhance BDNF bioavailability. Thus, we hypothesized that lower circulating BDNF levels (via lessened dopamine and/or glutamate release) underpin IGN in divers, while testing if BDNF loss is associated with increased OxS. Methods: To mimic IGN, we administered a deep narcosis test via a dry dive test (DDT) at 48 msw in a multiplace hyperbaric chamber to six well-trained divers. We collected: (1) saliva samples before DDT (T0), 25 msw (descending, T1), 48 msw (depth, T2), 25 msw (ascending, T3), 10 min after decompression (T4) to dopamine and/or reactive oxygen species (ROS) levels; (2) blood and urine samples at T0 and T4 for OxS too. We administered cognitive tests at T0, T2, and re-evaluated the divers at T4. Results: At 48 msw, all subjects experienced IGN, as revealed by the cognitive test failure. Dopamine and total antioxidant capacity (TAC) reached a nadir at T2 when ROS emission was maximal. At decompression (T4), a marked drop of BDNF/glutamate content was evidenced, coinciding with a persisting decline in dopamine and cognitive capacity. Conclusions: Divers encounter IGN at – 48 msw, exhibiting a marked loss in circulating dopamine levels, likely accounting for BDNF-dependent impairment of mental capacity and heightened OxS. The decline in dopamine and BDNF appears to persist at decompression; thus, boosting dopamine/BDNF signaling via pharmacological or other intervention types might attenuate IGN in deep dives.
AB - Purpose: Divers can experience cognitive impairment due to inert gas narcosis (IGN) at depth. Brain-derived neurotrophic factor (BDNF) rules neuronal connectivity/metabolism to maintain cognitive function and protect tissues against oxidative stress (OxS). Dopamine and glutamate enhance BDNF bioavailability. Thus, we hypothesized that lower circulating BDNF levels (via lessened dopamine and/or glutamate release) underpin IGN in divers, while testing if BDNF loss is associated with increased OxS. Methods: To mimic IGN, we administered a deep narcosis test via a dry dive test (DDT) at 48 msw in a multiplace hyperbaric chamber to six well-trained divers. We collected: (1) saliva samples before DDT (T0), 25 msw (descending, T1), 48 msw (depth, T2), 25 msw (ascending, T3), 10 min after decompression (T4) to dopamine and/or reactive oxygen species (ROS) levels; (2) blood and urine samples at T0 and T4 for OxS too. We administered cognitive tests at T0, T2, and re-evaluated the divers at T4. Results: At 48 msw, all subjects experienced IGN, as revealed by the cognitive test failure. Dopamine and total antioxidant capacity (TAC) reached a nadir at T2 when ROS emission was maximal. At decompression (T4), a marked drop of BDNF/glutamate content was evidenced, coinciding with a persisting decline in dopamine and cognitive capacity. Conclusions: Divers encounter IGN at – 48 msw, exhibiting a marked loss in circulating dopamine levels, likely accounting for BDNF-dependent impairment of mental capacity and heightened OxS. The decline in dopamine and BDNF appears to persist at decompression; thus, boosting dopamine/BDNF signaling via pharmacological or other intervention types might attenuate IGN in deep dives.
KW - Brain-derived neurotrophic factor (BDNF)
KW - Deep diving
KW - Dopamine
KW - Narcosis
KW - Reactive oxygen species (ROS)
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UR - http://www.scopus.com/inward/citedby.url?scp=85139568230&partnerID=8YFLogxK
U2 - 10.1007/s00421-022-05055-6
DO - 10.1007/s00421-022-05055-6
M3 - Article
C2 - 36214902
AN - SCOPUS:85139568230
SN - 1439-6319
VL - 123
SP - 143
EP - 158
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
IS - 1
ER -