relaxing, anxiety-reducing (anxiolytic) effects at low doses, impaired
movement and memory storage at higher does, loss of consciousness
at still higher doses, and, at sufficiently high doses, death—too much
GABAergic inhibition in the brain shuts things down completely.Opium and opioids. The opium poppy, Papaver somniferum, has been
appreciated for its medicinal properties for thousands of years (Fig.
9.2). It was cultivated by the ancient Sumerians of Mesopotamia
(modern-day Iraq) five thousand years ago. They referred to the
opium poppy as the “joy plant,” suggesting they were well aware of its
potential to produce psychoactive effects of relaxation, pain relief, and
even euphoria (intense good feeling).
Prominent effects of the opium poppy are its ability to reduce the
perception of pain (analgesia), to suppress cough, and to slow the
motile muscle action of the intestines, making it useful as a treatment
for diarrhea. These medicinal properties of Papaver somniferum were
long ago found to be concentrated in a resinous secretion obtained by
carefully slitting the unripe seed pods. This secretion is called opium
(Greek opos = plant juice). Opium is good medicine.
Around 1804, Friedrich Wilhelm Serttirner (1783-1841), a young
apprentice pharmacist in Germany, made a remarkable discovery. He
isolated and purified a chemical substance from opium and demon-
strated that the effects of this substance, when ingested, produced the
analgesic, soporific, and euphoric effects of opium, except in a more
potent manner. He named this chemical constituent of opium mor-
phine, after Morpheus, the god of dreams in Greek myth.