title: The blueprint for stress can be found in invertebrates.
abstract: Through an extremely complicated equilibrium called homeostasis, all living organisms maintain their survival in the face of both externally and internally generated "stimuli". This apparent harmony is constantly challenged. Survival through successful adaptation is maintained as close to steady state as possible by adaptive responses, which may also be called perturbation responses since they have a constitutively defined dynamic capacity, i.e., an immediate limit, in a series of balancing and feedback activities reflecting an astounding array of biological, psychological and sociological behaviors. The broad spectrum of stimuli capable of engaging this protective response is remarkable. We define stress as a type of stimulation that is stronger and lasts for a longer duration, upsetting a typical perturbation response given its dynamic parameters. The stress response, which evolves out of the perturbation response, involves inducible signal molecules, i.e., cytokines. We surmise that the ability to exist in an ever-changing environment was a requirement for all life forms, including invertebrates and single celled organisms. It would be expected that these organisms exhibit both perturbation and stress responses. In this regard, we demonstrate that these organisms have mammalian-like signal molecule systems, i.e., opioid, and corresponding behaviors that are similar to those found in mammals with regard to both perturbation and stress responses. Thus, it would appear that these responses evolved first in simpler organisms and were then maintained and enhanced during evolution.
authors.affiliation: Neuroscience Research Institute, State University of New York at Old Westbury, Old Westbury, NY 11568, USA. gstefano@sunynri.org
authors.forename: George B
authors.initials: GB
authors.lastname: Stefano
authors.forename: Patrick
authors.initials: P
authors.lastname: Cadet
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.forename: Christos M
authors.initials: CM
authors.lastname: Rialas
authors.forename: Kirk
authors.initials: K
authors.lastname: Mantione
authors.forename: Danielle
authors.initials: D
authors.lastname: Benz
authors.forename: Rudy
authors.initials: R
authors.lastname: Fuentes
authors.forename: Federico
authors.initials: F
authors.lastname: Casares
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Fricchione
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Fulop
authors.forename: Brian
authors.initials: B
authors.lastname: Slingsby
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000502:physiology; D000818:Animals; D005075:Biological Evolution; D007448:Invertebrates / Q000502:physiology*; D018847:Opioid Peptides / Q000502:physiology; D013312:Stress, Physiological / Q000503:physiopathology*
chemical_list: D018847:Opioid Peptides; D000324:Adrenocorticotropic Hormone