"Nitric Oxide (NO) is involved in the development of the bonding and smell recognition that occurs in ewes within 2 hour of giving birth. Inhibition of nNOS blocks formation of that olfactory memory, and this blockage can be reversed by infusion of NO into the olfactory bulb. [37] Oxytocin is essential in the formation of normal social attachment in mice. [38] Reduction in oxytocin release following epidural anesthesia in heifers preceded a reduction in maternal bonding type behaviors[39]. Activation of the oxytocin receptor causes activation of nitric oxide synthase. [40] The connections that mediate maternal bonding can occur in the space of a few hours[41], limiting the distance over which axons must migrate to form these new connections."
-
This sounds like good confirmation that the post-partum maternal-infant bond was strengthened via the backfloating/reclining mother humming (singing with mouth closed, producing nasal Nitric Oxide in Paranasal sinuses) into the face of the nasal-inhaling oral-feeding infant, transmitting antibiotic NO (killing airway microbial pathogens while simultaneously increasing the social bond and smell recognition and axonal development), typical in mammals but usually thought weaker in hominoids due to decreased olfactional abilities. This correlates to facial hair loss (prevents NO diffusion) in post-pubescent pre-menopause females, plausibly non-pathological hypothryroidy, long scalp hair, infant clinging ability. It also fits with childhood mumps being correlated to post-weaned (no more direct facial NO transmission) pre-pubertal assistive dive-foraging in shallow waters, better hydrodynamic sub-mandible profile due to enlargement of the salivary parotid glands.
Chicken pox and measles also occur at this time period, but I don't know what possible advantage they might have provided to human ancestors 1ma, if any, possibly chicken pox was a factor in saltwater immersion or sweating.
Newborns don't weep tears nor eccrine sweat AFAIK, possibly respiratory NO from the mother is required, for some unknown reason. Gorilla mothers transmit NO to their newborns due to their nasal breathing with circular laryngeal air sac breathing producing a guttaral vocal chord vibration (similar to their inhaled/exhaled laughter, unlike human exhale-only laughter). This is why human mothers must hum to newborns to transmit NO as human ancestors lost the laryngeal air sac and circular breathing during the transition from upright float-sit-foraging to upright-pluck-foraging to dive-forage-backfloating. Other ape mothers wheeze (vocalize) in and out while looking down nursing, human mothers hum outwards nasally or sing lullabies (language uses many partial hum-sounds in speech such as -m-n-r-l-s-sh, some implosive, some expulsive.
Formation of olfactory memories mediated by nitric...[Nature. 1997] - PubMed Result
Hat tip to Daedulus at:
Stranger than you can imagine
37. Kendrick KM, Guevara-Guzman R, Zorrilla J, Hinton MR, Broad KD, Mimmack M, Ohkura S. Formation of olfactory memories mediated by nitric oxide. Nature. 1997 Aug 14;388(6643):670-4.
38. Jennifer N. Ferguson, J. Matthew Aldag, Thomas R. Insel, and Larry J. Young. Oxytocin in the medial amygdale is essential for social recognition in the mouse. Journal Neuroscience, October 15, 2001, 21 (20):8278-8285.
39. G. L. Williams, O. S. Gazal, L. S. Leshin, R. L. Stanko, and L. L. Anderson. Physiological regulation of maternal behavior in heifers Biology of Reproduction 65, 295-300 (2001).
40. Gerald Gimpl and Falk Fahrenholz. The oxytocin receptor system: structure, function, and regulation. Physiological reviews vol. 81, No. 2, 629-683, April 2001.
41. Okere CO, Kaba H. Increased expression of neuronal nitric oxide synthase mRNA in the accessory olfactory bulb during the formation of olfactory recognition memory in mice. Eur J Neurosci. 2000 Dec;12(12):4552-6.
-
ps. This is not medical advice, it is research into hypothesized archaic seashore human ancestor dive-forager behavior and physiology. Consult your primary care physician for questions on the role of Nitric Oxide in breast feeding of newborns.
Also of potential interest: Role of low basal NO in ... vascular abnormalities
Stranger than you can imagine: Role of low basal NO in capillary and vascular abnormalities
