The similarity between NDE and ketamine experiences suggests that
some near-death experiences will be due to blockade of N-P receptors.
241–50, 247–9 A sudden fall in oxygen or blood sugar, which may (for
example) result from interruption of the blood supply during a heart
attack, has been shown to cause a flood release of glutamate.31
Epileptic attacks, head injuries and too much carbon dioxide can also
produce a flood.505–7, 451 Glutamate turns the receptor lock, opening
tunnels so that “the sea” rushes in. The cells swell and burst if the
stimulation is excessive and prolonged. Thus too much glutamate overexcites
cells, which die. Ketamine can prevent the brain damage that
results via the same mechanism that produces psychedelic effects: blockade
of the tunnels so that “the sea” cannot enter.507, 527, 547, 618
This discovery led me to the prediction that the brain would have a
natural protective mechanism against the glutamate flood.241–50, 247–9 This
protection could be a counter-flood of natural tunnel blockers. The
resulting block will produce ketamine-like psychedelic effects as the
two phenomena are linked. While a person is having a NDE the brain
is preserving itself from damage. The link is tunnel blockade, a block
that can happen naturally, for example as a protective brain response
if oxygen falls after a heart attack, or that can be provided by ketamine.
It is this block that can result in a NDE, not the glutamate
flood itself. The degree of damage and the mental state that result depend on the final balance between toxic and protective forces, a
form of battle between “good and evil” played out at the chemical
level.
Patients who were oxygen-deprived for long periods and had
profound near-death experiences sometimes survived the episode with
unimpaired brain function, to the astonishment of their doctors.512 The
lack of damage may result from a very effective mechanism for blocking
over-excitation. So people who can have a NDE are less likely to
suffer brain damage when the blood supply to the brain is cut off.
These may be the same group as those who report “emergence
phenomena” after ketamine. According to Michael Sabom, author of
Recollections of Death: a Medical Investigation, around 40% of the
population have had some form of NDE when the very widest definition
is used, although unpublished work by Peter Fenwick at the
Maudsley hospital in London, indicates a much lower figure amongst
those who had “clinically died!”512 The percentage reporting emergence
phenomena after ketamine anesthesia is also close to 40% in
many studies.1, 213, 328, 456, 460, 513 Until recently, the figure Parke-Davis gave
on their Ketalar® data sheet was 12%. This was too low, and has been
dropped from the latest data sheet.466
A natural tunnel blocker will protect the brain from damage while
generating a state of being that also holds the flood of overwhelming
anxiety at bay. The NDE may be beneficial for the physical brain as
well as having the potential for a positive mental outcome. The benefit
may be even greater where the forces of the psyche give the person
a strong message to “go back” in terms of a mythological drama, and
tell them that it is not their time to go. This might be the final expression
of the deep drive in the mind to survive.